1. WeatherSpark.com
  2. United States
  3. California

Climate and Average Weather Year Round in Healdsburg California, United States

In Healdsburg, the summers are long, warm, arid, and mostly clear and the winters are short, cold, wet, and partly cloudy. Over the course of the year, the temperature typically varies from 37°F to 85°F and is rarely below 28°F or above 96°F.

Based on the tourism score, the best time of year to visit Healdsburg for warm-weather activities is from mid June to early September.

Climate in Healdsburg

coolcomfortablewarmcoolJanFebMarAprMayJunJulAugSepOctNovDecNowNow92%92%41%41%clearovercastprecipitation: 6.1 inprecipitation: 6.1 in0.0 in0.0 inmuggy: 0%muggy: 0%0%0%drydrytourism score: 6.6tourism score: 6.60.50.5
Healdsburg weather by month. Click on each chart for more information.

The warm season lasts for 4.2 months, from June 2 to October 8, with an average daily high temperature above 79°F. The hottest month of the year in Healdsburg is July, with an average high of 85°F and low of 53°F.

The cool season lasts for 2.7 months, from November 24 to February 15, with an average daily high temperature below 61°F. The coldest month of the year in Healdsburg is December, with an average low of 38°F and high of 57°F.

Average High and Low Temperature in Healdsburg

Average High and Low Temperature in HealdsburgwarmcoolcoolJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FDec 3156°FDec 3156°FJul 1485°FJul 1485°F37°F37°F53°F53°FJun 279°FJun 279°FOct 879°FOct 879°FFeb 1561°FFeb 1561°F50°F50°F48°F48°F41°F41°F41°F41°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 57°F61°F65°F70°F76°F82°F85°F84°F83°F76°F64°F57°F
Temp. 46°F50°F52°F55°F60°F65°F66°F66°F64°F59°F52°F46°F
Low 38°F41°F42°F44°F48°F52°F53°F53°F51°F47°F42°F38°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 Healdsburg

Average Hourly Temperature in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec12 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 coldcoldcoolcoolcomfortablewarmvery coldvery cold
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.

Talagante, Chile (6,007 miles away) is the far-away foreign place with temperatures most similar to Healdsburg (view comparison).

Map
Marker
© OpenStreetMap contributors

Compare Healdsburg to another city:

Map

In Healdsburg, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.

The clearer part of the year in Healdsburg begins around May 17 and lasts for 5.2 months, ending around October 22.

The clearest month of the year in Healdsburg is July, during which on average the sky is clear, mostly clear, or partly cloudy 90% of the time.

The cloudier part of the year begins around October 22 and lasts for 6.8 months, ending around May 17.

The cloudiest month of the year in Healdsburg is February, during which on average the sky is overcast or mostly cloudy 58% of the time.

Cloud Cover Categories in Healdsburg

Cloud Cover Categories in HealdsburgclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2692%Jul 2692%Jan 1041%Jan 1041%May 1766%May 1766%Oct 2267%Oct 2267%NowNowclearovercastpartly cloudymostly clearmostly cloudy
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 58%58%54%45%34%20%10%10%14%30%49%55%
Clearer 42%42%46%55%66%80%90%90%86%70%51%45%

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

The wetter season lasts 5.5 months, from October 28 to April 11, with a greater than 18% chance of a given day being a wet day. The month with the most wet days in Healdsburg is February, with an average of 9.6 days with at least 0.04 inches of precipitation.

The drier season lasts 6.5 months, from April 11 to October 28. The month with the fewest wet days in Healdsburg is July, with an average of 0.2 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 Healdsburg is February, with an average of 9.5 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 35% on February 20.

Daily Chance of Precipitation in Healdsburg

Daily Chance of Precipitation in HealdsburgwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Feb 2035%Feb 2035%Jul 160%Jul 160%Oct 2818%Oct 2818%Apr 1118%Apr 1118%NowNowrain
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 9.5d9.5d8.8d4.9d2.6d0.8d0.2d0.2d1.1d3.5d7.5d9.8d
Mixed 0.1d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.1d
Any 9.7d9.6d8.8d4.9d2.6d0.8d0.2d0.2d1.1d3.5d7.5d10.0d

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. Healdsburg experiences extreme seasonal variation in monthly rainfall.

The rainy period of the year lasts for 8.2 months, from September 25 to June 2, with a sliding 31-day rainfall of at least 0.5 inches. The month with the most rain in Healdsburg is February, with an average rainfall of 6.1 inches.

The rainless period of the year lasts for 3.8 months, from June 2 to September 25. The month with the least rain in Healdsburg is July, with an average rainfall of 0.0 inches.

Average Monthly Rainfall in Healdsburg

Average Monthly Rainfall in HealdsburgrainrainJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 in12 in12 in14 in14 inFeb 166.1 inFeb 166.1 inJul 280.0 inJul 280.0 inDec 196.0 inDec 196.0 inSep 250.5 inSep 250.5 inJun 20.5 inJun 20.5 in
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 5.7″6.1″4.3″1.8″0.8″0.3″0.0″0.1″0.3″1.6″4.1″6.0″

The length of the day in Healdsburg varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 28 minutes of daylight; the longest day is June 20, with 14 hours, 52 minutes of daylight.

Hours of Daylight and Twilight in Healdsburg

Hours of Daylight and Twilight in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 8 minMar 1912 hr, 8 minMar 1914 hr, 52 minJun 2014 hr, 52 minJun 2012 hr, 10 minSep 2212 hr, 10 minSep 229 hr, 28 minDec 219 hr, 28 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 9.8h10.8h12.0h13.3h14.3h14.8h14.5h13.6h12.4h11.1h10.1h9.5h

The earliest sunrise is at 5:46 AM on June 13, and the latest sunrise is 1 hour, 54 minutes later at 7:40 AM on November 2. The earliest sunset is at 4:49 PM on December 6, and the latest sunset is 3 hours, 50 minutes later at 8:40 PM on June 27.

Daylight saving time (DST) is observed in Healdsburg 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 Healdsburg

Sunrise & Sunset with Twilight and Daylight Saving Time in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:46 AMJun 135:46 AM8:40 PMJun 278:40 PMJun 27Dec 64:49 PMDec 64:49 PM7:40 AMNov 27:40 AMNov 2Mar 10DSTMar 10DSTDSTNov 3DSTNov 3daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
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 Healdsburg

Solar Elevation and Azimuth in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec12 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 AM0001010101020202030303040404050506060700001010102020202030304040505060702875NowNow
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 Healdsburg

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 Healdsburg, 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, remaining a virtually constant 0% throughout.

Humidity Comfort Levels in Healdsburg

Humidity Comfort Levels in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jan 20%Jan 20%Sep 130%Sep 130%NowNowcomfortablecomfortabledrydry
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 0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d

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 Healdsburg experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.1 months, from March 5 to July 10, with average wind speeds of more than 7.0 miles per hour. The windiest month of the year in Healdsburg is May, with an average hourly wind speed of 7.7 miles per hour.

The calmer time of year lasts for 7.9 months, from July 10 to March 5. The calmest month of the year in Healdsburg is October, with an average hourly wind speed of 6.2 miles per hour.

Average Wind Speed in Healdsburg

Average Wind Speed in HealdsburgwindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph1 mph1 mph2 mph2 mph3 mph3 mph4 mph4 mph5 mph5 mph6 mph6 mph7 mph7 mph8 mph8 mph9 mph9 mph10 mph10 mph11 mph11 mphJun 57.8 mphJun 57.8 mphOct 206.1 mphOct 206.1 mphMar 57.0 mphMar 57.0 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) 6.66.97.27.47.77.76.86.56.36.26.56.8

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

The wind is most often from the west for 7.1 months, from March 7 to October 10, with a peak percentage of 74% on July 29. The wind is most often from the north for 4.9 months, from October 10 to March 7, with a peak percentage of 43% on January 1.

Wind Direction in Healdsburg

Wind Direction in HealdsburgNWNJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestnorthsoutheast
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).

Healdsburg 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 2.5 months, from August 16 to October 31, with an average temperature above 55°F. The month of the year in Healdsburg with the warmest water is September, with an average temperature of 56°F.

The time of year with cooler water lasts for 3.1 months, from March 26 to June 30, with an average temperature below 52°F. The month of the year in Healdsburg with the coolest water is May, with an average temperature of 51°F.

Average Water Temperature in Healdsburg

Average Water Temperature in HealdsburgwarmcoolJanFebMarAprMayJunJulAugSepOctNovDec48°F48°F50°F50°F52°F52°F54°F54°F56°F56°F58°F58°F60°F60°FSep 2156°FSep 2156°F51°FMay 1051°FMay 10Aug 1655°FAug 1655°FOct 3155°FOct 3155°FMar 2652°FMar 2652°FJun 3052°FJun 3052°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
WaterJanFebMarAprMayJunJulAugSepOctNovDec
Temperature 53°F53°F53°F52°F51°F52°F53°F55°F56°F56°F55°F53°F

To characterize how pleasant the weather is in Healdsburg 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 Healdsburg for general outdoor tourist activities is from mid June to early September, with a peak score in the last week of July.

Tourism Score in Healdsburg

Tourism Score in Healdsburgbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.66.60.50.5NowNowtemperaturetemperature 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 Healdsburg for hot-weather activities is from mid June to late August, with a peak score in the first week of July.

Beach/Pool Score in Healdsburg

Beach/Pool Score in Healdsburgbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810102.82.80.00.0NowNowtemperaturetemperature 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 Healdsburg typically lasts for 9.1 months (278 days), from around February 24 to around November 27, rarely starting before January 5 or after March 24, and rarely ending before November 7 or after December 29.

Time Spent in Various Temperature Bands and the Growing Season in Healdsburg

Time Spent in Various Temperature Bands and the Growing Season in Healdsburggrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Feb 2450%Feb 2450%Nov 2750%Nov 2790%Mar 2490%Mar 2490%Nov 790%Nov 710%Jan 510%Jan 510%Dec 2910%Dec 29Jul 19100%Jul 19100%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 Healdsburg should appear around February 14, only rarely appearing before February 3 or after March 3.

Growing Degree Days in Healdsburg

Growing Degree Days in HealdsburgJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°FFeb 1490°FFeb 1490°FJun 7900°FJun 7900°FAug 31,800°FAug 31,800°FDec 313,136°FDec 313,136°FNowNow
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 3.5 months, from May 8 to August 24, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest month of the year in Healdsburg is July, with an average of 8.3 kWh.

The darker period of the year lasts for 3.6 months, from November 2 to February 20, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest month of the year in Healdsburg is December, with an average of 2.0 kWh.

Average Daily Incident Shortwave Solar Energy in Healdsburg

Average Daily Incident Shortwave Solar Energy in HealdsburgbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWh10 kWh10 kWhJun 288.5 kWhJun 288.5 kWhDec 252.0 kWhDec 252.0 kWhMay 87.2 kWhMay 87.2 kWhAug 247.2 kWhAug 247.2 kWhNov 23.3 kWhNov 23.3 kWhFeb 203.3 kWhFeb 203.3 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) 2.33.14.66.27.48.38.37.46.04.32.72.0

For the purposes of this report, the geographical coordinates of Healdsburg are 38.610 deg latitude, -122.869 deg longitude, and 105 ft elevation.

The topography within 2 miles of Healdsburg contains very significant variations in elevation, with a maximum elevation change of 886 feet and an average elevation above sea level of 169 feet. Within 10 miles contains very significant variations in elevation (3,110 feet). Within 50 miles contains large variations in elevation (6,083 feet).

The area within 2 miles of Healdsburg is covered by cropland (55%) and artificial surfaces (30%), within 10 miles by trees (29%) and cropland (28%), and within 50 miles by shrubs (28%) and water (26%).

This report illustrates the typical weather in Healdsburg, 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 Healdsburg.

For each station, the records are corrected for the elevation difference between that station and Healdsburg 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 Healdsburg is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Healdsburg 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 Healdsburg 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.