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Climate and Average Weather Year Round in Mount Vernon Washington, United States

In Mount Vernon, the summers are short, comfortable, and partly cloudy and the winters are very cold, wet, and mostly cloudy. Over the course of the year, the temperature typically varies from 36°F to 76°F and is rarely below 25°F or above 84°F.

Based on the tourism score, the best time of year to visit Mount Vernon for warm-weather activities is from early July to late August.

Climate in Mount Vernon

coldcoolcomfortablewarmcomfortablecoolcoldJanFebMarAprMayJunJulAugSepOctNovDecNowNow72%72%27%27%overcastclearprecipitation: 8.3 inprecipitation: 8.3 in0.8 in0.8 inmuggy: 1%muggy: 1%0%0%drydrytourism score: 6.1tourism score: 6.10.10.1
Mount Vernon weather by month. Click on each chart for more information.

The warm season lasts for 2.7 months, from June 23 to September 15, with an average daily high temperature above 70°F. The hottest month of the year in Mount Vernon is August, with an average high of 75°F and low of 53°F.

The cool season lasts for 3.4 months, from November 13 to February 26, with an average daily high temperature below 51°F. The coldest month of the year in Mount Vernon is December, with an average low of 36°F and high of 45°F.

Average High and Low Temperature in Mount Vernon

Average High and Low Temperature in Mount VernonwarmcoolcoolJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FDec 2245°FDec 2245°FAug 276°FAug 276°F36°F36°F54°F54°FJun 2370°FJun 2370°FSep 1570°FSep 1570°FNov 1351°FNov 1351°FFeb 2651°FFeb 2651°F52°F52°F51°F51°F41°F41°F38°F38°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.
AverageJanFebMarAprMayJunJulAugSepOctNovDec
High 46°F50°F53°F58°F64°F69°F74°F75°F69°F60°F51°F45°F
Temp. 41°F42°F46°F49°F54°F59°F63°F63°F59°F52°F45°F40°F
Low 37°F37°F40°F42°F47°F51°F53°F53°F50°F46°F40°F36°F

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in Mount Vernon

Average Hourly Temperature in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNowNowvery coldvery coldcoldcoolcoolcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Verea, Spain (5,023 miles away) and Saint-Sylvain, France (4,876 miles) are the far-away foreign places with temperatures most similar to Mount Vernon (view comparison).

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In Mount Vernon, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Mount Vernon begins around June 19 and lasts for 3.5 months, ending around October 3.

The clearest month of the year in Mount Vernon is August, during which on average the sky is clear, mostly clear, or partly cloudy 67% of the time.

The cloudier part of the year begins around October 3 and lasts for 8.5 months, ending around June 19.

The cloudiest month of the year in Mount Vernon is December, during which on average the sky is overcast or mostly cloudy 73% of the time.

Cloud Cover Categories in Mount Vernon

Cloud Cover Categories in Mount VernonclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Aug 272%Aug 272%Jan 1927%Jan 1927%Jun 1949%Jun 1949%Oct 349%Oct 349%NowNowclearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.
FractionJanFebMarAprMayJunJulAugSepOctNovDec
Cloudier 73%70%69%64%57%51%34%33%43%59%71%73%
Clearer 27%30%31%36%43%49%66%67%57%41%29%27%

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Mount Vernon varies significantly throughout the year.

The wetter season lasts 6.4 months, from October 10 to April 23, with a greater than 34% chance of a given day being a wet day. The month with the most wet days in Mount Vernon is November, with an average of 17.0 days with at least 0.04 inches of precipitation.

The drier season lasts 5.6 months, from April 23 to October 10. The month with the fewest wet days in Mount Vernon is July, with an average of 3.9 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Mount Vernon is November, with an average of 16.8 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 58% on November 17.

Daily Chance of Precipitation in Mount Vernon

Daily Chance of Precipitation in Mount VernonwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Nov 1759%Nov 1759%Jul 3110%Jul 3110%Oct 1034%Oct 1034%Apr 2334%Apr 2334%NowNowrainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).
Days ofJanFebMarAprMayJunJulAugSepOctNovDec
Rain 14.6d13.2d14.6d11.4d8.8d7.0d3.9d4.1d6.8d12.4d16.8d15.6d
Mixed 0.5d0.3d0.2d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.1d0.6d
Snow 0.2d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.1d0.2d
Any 15.4d13.5d14.8d11.4d8.8d7.0d3.9d4.1d6.8d12.4d17.0d16.4d

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Mount Vernon experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Mount Vernon. The month with the most rain in Mount Vernon is November, with an average rainfall of 8.3 inches.

The month with the least rain in Mount Vernon is July, with an average rainfall of 0.9 inches.

Average Monthly Rainfall in Mount Vernon

Average Monthly Rainfall in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 in12 in12 in14 in14 inNov 198.3 inNov 198.3 inJul 290.8 inJul 290.8 inNowNow
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Rainfall 6.4″5.4″4.7″3.3″2.3″1.8″0.9″1.1″2.1″5.2″8.3″6.8″

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Mount Vernon experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 1.2 months, from December 11 to January 18, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Mount Vernon is December, with an average snowfall of 1.4 inches.

The snowless period of the year lasts for 11 months, from January 18 to December 11. The least snow falls around July 26, with an average total accumulation of 0.0 inches.

Average Monthly Snowfall in Mount Vernon

Average Monthly Snowfall in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 inDec 291.8 inDec 291.8 inJul 260.0 inJul 260.0 inJan 181.0 inJan 181.0 inNowNow
The average snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Snowfall 1.1″0.3″0.2″0.0″0.0″0.0″0.0″0.0″0.0″0.0″0.2″1.4″

The length of the day in Mount Vernon varies extremely over the course of the year. In 2024, the shortest day is December 21, with 8 hours, 19 minutes of daylight; the longest day is June 20, with 16 hours, 7 minutes of daylight.

Hours of Daylight and Twilight in Mount Vernon

Hours of Daylight and Twilight in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 9 minMar 1912 hr, 9 minMar 1916 hr, 7 minJun 2016 hr, 7 minJun 2012 hr, 12 minSep 2212 hr, 12 minSep 228 hr, 19 minDec 218 hr, 19 minDec 21nightnightdayNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.
Hours ofJanFebMarAprMayJunJulAugSepOctNovDec
Daylight 8.8h10.2h12.0h13.7h15.3h16.0h15.6h14.2h12.5h10.8h9.2h8.4h

The earliest sunrise is at 5:07 AM on June 16, and the latest sunrise is 2 hours, 54 minutes later at 8:00 AM on December 31. The earliest sunset is at 4:14 PM on December 11, and the latest sunset is 5 hours, 1 minute later at 9:15 PM on June 24.

Daylight saving time (DST) is observed in Mount Vernon during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3.

Sunrise & Sunset with Twilight and Daylight Saving Time in Mount Vernon

Sunrise & Sunset with Twilight and Daylight Saving Time in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 165:07 AMJun 165:07 AM9:15 PMJun 249:15 PMJun 24Dec 114:14 PMDec 114:14 PM8:00 AMDec 318:00 AMDec 31Mar 10DSTMar 10DSTDSTNov 3DSTNov 3daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunsetNowNow
The solar day over the course of the year 2024. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in Mount Vernon

Solar Elevation and Azimuth in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AM00010101010202030304040506000010101020202020303040405050601865NowNow
northeastsouthwest
Solar elevation and azimuth over the course of the year 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

Moon Rise, Set & Phases in Mount Vernon

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in Mount Vernon, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 1% of 1% throughout.

Humidity Comfort Levels in Mount Vernon

Humidity Comfort Levels in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Mar 70%Mar 70%Aug 31%Aug 31%NowNowcomfortablecomfortabledrydryhumidhumid
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.
JanFebMarAprMayJunJulAugSepOctNovDec
Muggy days 0.0d0.0d0.0d0.0d0.0d0.1d0.2d0.2d0.0d0.0d0.0d0.0d

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Mount Vernon experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 6.0 months, from October 14 to April 14, with average wind speeds of more than 4.2 miles per hour. The windiest month of the year in Mount Vernon is December, with an average hourly wind speed of 5.7 miles per hour.

The calmer time of year lasts for 6.0 months, from April 14 to October 14. The calmest month of the year in Mount Vernon is August, with an average hourly wind speed of 2.8 miles per hour.

Average Wind Speed in Mount Vernon

Average Wind Speed in Mount VernonwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph1 mph1 mph2 mph2 mph3 mph3 mph4 mph4 mph5 mph5 mph6 mph6 mph7 mph7 mph8 mph8 mph9 mph9 mphDec 35.8 mphDec 35.8 mphAug 52.7 mphAug 52.7 mphOct 144.2 mphOct 144.2 mphApr 144.2 mphApr 144.2 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Wind Speed (mph) 5.55.24.94.23.53.22.82.83.34.35.55.7

The predominant average hourly wind direction in Mount Vernon varies throughout the year.

The wind is most often from the south for 1.3 months, from March 12 to April 21 and for 3.9 weeks, from September 21 to October 18, with a peak percentage of 39% on March 23. The wind is most often from the west for 5.0 months, from April 21 to September 21, with a peak percentage of 57% on June 29. The wind is most often from the east for 4.8 months, from October 18 to March 12, with a peak percentage of 55% on January 1.

Wind Direction in Mount Vernon

Wind Direction in Mount VernonESWSEJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwesteastsouthnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Mount Vernon is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average water temperature experiences some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.0 months, from June 21 to September 19, with an average temperature above 53°F. The month of the year in Mount Vernon with the warmest water is August, with an average temperature of 55°F.

The time of year with cooler water lasts for 4.1 months, from December 2 to April 7, with an average temperature below 48°F. The month of the year in Mount Vernon with the coolest water is February, with an average temperature of 46°F.

Average Water Temperature in Mount Vernon

Average Water Temperature in Mount VernonwarmcoolcoolJanFebMarAprMayJunJulAugSepOctNovDec42°F42°F44°F44°F46°F46°F48°F48°F50°F50°F52°F52°F54°F54°F56°F56°F58°F58°F60°F60°FAug 255°FAug 255°F46°FJan 2946°FJan 29Jun 2153°FJun 2153°FSep 1953°FSep 1953°FDec 248°FDec 248°FApr 748°FApr 748°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
WaterJanFebMarAprMayJunJulAugSepOctNovDec
Temperature 46°F46°F47°F48°F51°F53°F55°F55°F54°F51°F49°F47°F

To characterize how pleasant the weather is in Mount Vernon throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Mount Vernon for general outdoor tourist activities is from early July to late August, with a peak score in the last week of July.

Tourism Score in Mount Vernon

Tourism Score in Mount Vernonbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.16.10.10.1NowNow cloudscloudsprecipitationprecipitationtourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Mount Vernon for hot-weather activities is from mid July to mid August, with a peak score in the first week of August.

Beach/Pool Score in Mount Vernon

Beach/Pool Score in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec002244668810101.81.80.00.0NowNow cloudscloudsprecipitationprecipitationbeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in Mount Vernon typically lasts for 7.8 months (239 days), from around March 18 to around November 13, rarely starting before February 21 or after April 21, and rarely ending before October 25 or after December 5.

Time Spent in Various Temperature Bands and the Growing Season in Mount Vernon

Time Spent in Various Temperature Bands and the Growing Season in Mount Vernongrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Mar 1850%Mar 1850%Nov 1350%Nov 1390%Apr 2190%Apr 2190%Oct 2590%Oct 2510%Feb 2110%Feb 2110%Dec 510%Dec 50%Jan 20%Jan 2Aug 1100%Aug 1100%NowNowvery coldcoldcoolcomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Mount Vernon should appear around April 21, only rarely appearing before March 31 or after May 13.

Growing Degree Days in Mount Vernon

Growing Degree Days in Mount VernonJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°FApr 2190°FApr 2190°FJul 28900°FJul 28900°FDec 311,752°FDec 311,752°F
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.3 months, from May 12 to August 20, with an average daily incident shortwave energy per square meter above 5.4 kWh. The brightest month of the year in Mount Vernon is July, with an average of 6.5 kWh.

The darker period of the year lasts for 3.9 months, from October 23 to February 19, with an average daily incident shortwave energy per square meter below 2.0 kWh. The darkest month of the year in Mount Vernon is December, with an average of 0.9 kWh.

Average Daily Incident Shortwave Solar Energy in Mount Vernon

Average Daily Incident Shortwave Solar Energy in Mount VernonbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhJul 206.6 kWhJul 206.6 kWhDec 240.8 kWhDec 240.8 kWhMay 125.4 kWhMay 125.4 kWhOct 232.0 kWhOct 232.0 kWhFeb 192.0 kWhFeb 192.0 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Solar Energy (kWh) 1.11.82.94.45.56.06.55.74.12.41.20.9

For the purposes of this report, the geographical coordinates of Mount Vernon are 48.421 deg latitude, -122.334 deg longitude, and 85 ft elevation.

The topography within 2 miles of Mount Vernon contains significant variations in elevation, with a maximum elevation change of 801 feet and an average elevation above sea level of 83 feet. Within 10 miles contains significant variations in elevation (3,980 feet). Within 50 miles also contains extreme variations in elevation (10,768 feet).

The area within 2 miles of Mount Vernon is covered by artificial surfaces (72%) and cropland (19%), within 10 miles by cropland (34%) and trees (28%), and within 50 miles by trees (43%) and water (28%).

This report illustrates the typical weather in Mount Vernon, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Mount Vernon.

For each station, the records are corrected for the elevation difference between that station and Mount Vernon according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at Mount Vernon is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Mount Vernon and a given station.

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of Mount Vernon and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

Please review our full terms contained on our Terms of Service page.