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Climate and Average Weather Year Round in Fairbury Illinois, United States

In Fairbury, the summers are long, warm, humid, and wet; the winters are freezing, snowy, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 19°F to 85°F and is rarely below 0°F or above 93°F.

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

Climate in Fairbury

very coldcoldcoolwarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDecNowNow70%70%43%43%clearovercastprecipitation: 3.8 inprecipitation: 3.8 in1.3 in1.3 inmuggy: 60%muggy: 60%0%0%drydrytourism score: 6.5tourism score: 6.50.10.1
Fairbury weather by month. Click on each chart for more information.

The warm season lasts for 4.2 months, from May 17 to September 24, with an average daily high temperature above 75°F. The hottest month of the year in Fairbury is July, with an average high of 85°F and low of 65°F.

The cold season lasts for 3.0 months, from December 2 to March 1, with an average daily high temperature below 44°F. The coldest month of the year in Fairbury is January, with an average low of 20°F and high of 34°F.

Average High and Low Temperature in Fairbury

Average High and Low Temperature in FairburywarmcoldcoldJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FJan 2933°FJan 2933°FJul 1985°FJul 1985°F19°F19°F66°F66°FMay 1775°FMay 1775°FSep 2475°FSep 2475°FDec 244°FDec 244°FMar 144°FMar 144°F53°F53°F53°F53°F29°F29°F27°F27°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 34°F38°F51°F64°F74°F82°F85°F83°F77°F65°F51°F38°F
Temp. 26°F29°F40°F52°F63°F72°F75°F73°F66°F54°F42°F30°F
Low 20°F23°F32°F43°F53°F62°F65°F63°F55°F44°F34°F24°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 Fairbury

Average Hourly Temperature in FairburyJanFebMarAprMayJunJulAugSepOctNovDec12 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 AMNowNowfreezingvery coldcoldcoldcoolcoolcomfortablewarmvery coldfreezing
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.

Lakkha Nëvre, Russia (5,944 miles away); Uzgen, Kyrgyzstan (6,697 miles); and Seongnam-si, South Korea (6,590 miles) are the far-away foreign places with temperatures most similar to Fairbury (view comparison).

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In Fairbury, 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 Fairbury begins around June 14 and lasts for 4.4 months, ending around October 28.

The clearest month of the year in Fairbury is August, during which on average the sky is clear, mostly clear, or partly cloudy 68% of the time.

The cloudier part of the year begins around October 28 and lasts for 7.6 months, ending around June 14.

The cloudiest month of the year in Fairbury is December, during which on average the sky is overcast or mostly cloudy 56% of the time.

Cloud Cover Categories in Fairbury

Cloud Cover Categories in FairburyclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Aug 2670%Aug 2670%Dec 2943%Dec 2943%Jun 1456%Jun 1456%Oct 2856%Oct 2856%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 56%55%52%49%49%43%35%32%33%40%50%56%
Clearer 44%45%48%51%51%57%65%68%67%60%50%44%

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

The wetter season lasts 5.8 months, from March 27 to September 21, with a greater than 27% chance of a given day being a wet day. The month with the most wet days in Fairbury is June, with an average of 11.5 days with at least 0.04 inches of precipitation.

The drier season lasts 6.2 months, from September 21 to March 27. The month with the fewest wet days in Fairbury is January, with an average of 4.9 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 Fairbury is June, with an average of 11.5 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 40% on June 7.

Daily Chance of Precipitation in Fairbury

Daily Chance of Precipitation in FairburywetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jun 740%Jun 740%Jan 2814%Jan 2814%Jan 118%Jan 118%Mar 2727%Mar 2727%Sep 2127%Sep 2127%NowNowrainsnowmixed
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 2.6d2.9d6.4d9.4d11.7d11.5d11.2d10.1d8.3d7.6d6.6d4.3d
Mixed 0.8d0.7d0.6d0.2d0.0d0.0d0.0d0.0d0.0d0.0d0.5d1.1d
Snow 1.5d1.2d0.4d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.2d1.2d
Any 4.9d4.8d7.4d9.7d11.7d11.5d11.2d10.1d8.3d7.6d7.2d6.5d

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. Fairbury experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Fairbury. The month with the most rain in Fairbury is June, with an average rainfall of 3.7 inches.

The month with the least rain in Fairbury is January, with an average rainfall of 1.0 inches.

Average Monthly Rainfall in Fairbury

Average Monthly Rainfall in FairburyJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 in7 in7 inJun 23.8 inJun 23.8 inJan 270.9 inJan 270.9 inAug 233.3 inAug 233.3 inOct 312.6 inOct 312.6 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 1.0″1.2″2.0″3.1″3.7″3.7″3.3″3.2″2.9″2.6″2.5″1.7″

Snowfall

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

The snowy period of the year lasts for 3.9 months, from November 24 to March 21, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Fairbury is January, with an average snowfall of 3.5 inches.

The snowless period of the year lasts for 8.1 months, from March 21 to November 24. The least snow falls around July 22, with an average total accumulation of 0.0 inches.

Average Monthly Snowfall in Fairbury

Average Monthly Snowfall in FairburysnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 inJan 313.7 inJan 313.7 inJul 220.0 inJul 220.0 inNov 241.0 inNov 241.0 inMar 211.0 inMar 211.0 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 3.5″3.4″1.3″0.2″0.0″0.0″0.0″0.0″0.0″0.0″0.5″2.7″

The length of the day in Fairbury varies significantly over the course of the year. In 2023, the shortest day is December 21, with 9 hours, 15 minutes of daylight; the longest day is June 21, with 15 hours, 6 minutes of daylight.

Hours of Daylight and Twilight in Fairbury

Hours of Daylight and Twilight in FairburyJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 8 minMar 2012 hr, 8 minMar 2015 hr, 6 minJun 2115 hr, 6 minJun 2112 hr, 10 minSep 2312 hr, 10 minSep 239 hr, 15 minDec 219 hr, 15 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 9.6h10.7h12.0h13.4h14.5h15.1h14.7h13.7h12.4h11.1h9.9h9.3h

The earliest sunrise is at 5:22 AM on June 14, and the latest sunrise is 2 hours, 6 minutes later at 7:27 AM on November 4. The earliest sunset is at 4:26 PM on December 8, and the latest sunset is 4 hours, 3 minutes later at 8:29 PM on June 28.

Daylight saving time (DST) is observed in Fairbury during 2023, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time in Fairbury

Sunrise & Sunset with Twilight and Daylight Saving Time in FairburyJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 145:22 AMJun 145:22 AM8:29 PMJun 288:29 PMJun 28Dec 84:26 PMDec 84:26 PM7:27 AMNov 47:27 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2023. 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 Fairbury

Solar Elevation and Azimuth in FairburyJanFebMarAprMayJunJulAugSepOctNovDec12 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 AM00010101010202020303030404040505060607000010101020202020303040405050602673NowNow
northeastsouthwest
Solar elevation and azimuth over the course of the year 2023. 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 2023. 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 Fairbury

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.

Fairbury experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.8 months, from May 27 to September 19, during which time the comfort level is muggy, oppressive, or miserable at least 15% of the time. The month with the most muggy days in Fairbury is July, with 17.8 days that are muggy or worse.

The month with the fewest muggy days in Fairbury is January, with 0.0 days that are muggy or worse.

Humidity Comfort Levels in Fairbury

Humidity Comfort Levels in FairburymuggyJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jan 270%Jan 270%Jul 2160%Jul 2160%May 2715%May 2715%Sep 1915%Sep 1915%oppressiveoppressivemuggymuggydrydrycomfortablecomfortablehumidhumidmiserablemiserable
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 0.0d0.0d0.0d0.3d3.0d10.7d17.8d15.3d5.9d0.7d0.0d0.0d

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 Fairbury experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 7.6 months, from October 8 to May 27, with average wind speeds of more than 10.0 miles per hour. The windiest month of the year in Fairbury is March, with an average hourly wind speed of 12.5 miles per hour.

The calmer time of year lasts for 4.4 months, from May 27 to October 8. The calmest month of the year in Fairbury is August, with an average hourly wind speed of 7.5 miles per hour.

Average Wind Speed in Fairbury

Average Wind Speed in FairburywindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mph16 mph16 mph18 mph18 mph20 mph20 mphMar 2312.8 mphMar 2312.8 mphAug 37.3 mphAug 37.3 mphOct 810.0 mphOct 810.0 mphMay 2710.0 mphMay 2710.0 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) 12.112.012.512.410.79.07.77.58.810.511.711.8

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

The wind is most often from the south for 8.0 months, from March 29 to November 28, with a peak percentage of 37% on November 10. The wind is most often from the west for 4.0 months, from November 28 to March 29, with a peak percentage of 40% on January 1.

Wind Direction in Fairbury

Wind Direction in FairburyWSWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsouthnortheast
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).

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

Tourism Score in Fairbury

Tourism Score in Fairburybest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.56.50.10.1precipitationprecipitationcloudscloudstemperaturetemperature tourism 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 Fairbury for hot-weather activities is from late June to late August, with a peak score in the third week of July.

Beach/Pool Score in Fairbury

Beach/Pool Score in Fairburybest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810105.65.60.00.0precipitationprecipitationcloudscloudstemperaturetemperature beach/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 Fairbury typically lasts for 6.0 months (185 days), from around April 15 to around October 16, rarely starting before March 29 or after May 3, and rarely ending before September 28 or after November 3.

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

Time Spent in Various Temperature Bands and the Growing Season in Fairburygrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Apr 1550%Apr 1550%Oct 1650%Oct 1690%May 390%May 390%Sep 2890%Sep 2810%Mar 2910%Mar 2910%Nov 310%Nov 30%Dec 110%Dec 11Jul 17100%Jul 17100%NowNowfrigidfreezingvery coldcoolcomfortablewarmhotcold
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 Fairbury should appear around April 4, only rarely appearing before March 21 or after April 20.

Growing Degree Days in Fairbury

Growing Degree Days in FairburyJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°F3,500°F3,500°F4,000°F4,000°FApr 489°FApr 489°FJun 11900°FJun 11900°FJul 191,800°FJul 191,800°FDec 313,548°FDec 313,548°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 3.8 months, from May 1 to August 26, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year in Fairbury is July, with an average of 6.7 kWh.

The darker period of the year lasts for 3.2 months, from November 4 to February 10, with an average daily incident shortwave energy per square meter below 2.8 kWh. The darkest month of the year in Fairbury is December, with an average of 1.8 kWh.

Average Daily Incident Shortwave Solar Energy in Fairbury

Average Daily Incident Shortwave Solar Energy in FairburybrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhJul 26.9 kWhJul 26.9 kWhDec 171.8 kWhDec 171.8 kWhMay 15.9 kWhMay 15.9 kWhAug 265.9 kWhAug 265.9 kWhFeb 102.8 kWhFeb 102.8 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) 2.13.04.25.46.26.76.76.15.13.62.41.8

For the purposes of this report, the geographical coordinates of Fairbury are 40.747 deg latitude, -88.515 deg longitude, and 682 ft elevation.

The topography within 2 miles of Fairbury is essentially flat, with a maximum elevation change of 56 feet and an average elevation above sea level of 678 feet. Within 10 miles is essentially flat (187 feet). Within 50 miles contains only modest variations in elevation (581 feet).

The area within 2 miles of Fairbury is covered by cropland (88%), within 10 miles by cropland (99%), and within 50 miles by cropland (94%).

This report illustrates the typical weather in Fairbury, 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 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Fairbury.

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