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Climate and Average Weather Year Round at St Athan Royal Air Force Base United Kingdom

At St Athan Royal Air Force Base, the summers are comfortable; the winters are long, very cold, wet, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 38°F to 68°F and is rarely below 29°F or above 77°F.

Based on the tourism score, the best time of year to visit St Athan Royal Air Force Base for warm-weather activities is from late June to early September.

Climate at St Athan Royal Air Force Base

coldcoolcomfortablecoolcoldJanFebMarAprMayJunJulAugSepOctNovDecNowNow57%57%33%33%overcastclearprecipitation: 3.3 inprecipitation: 3.3 in1.6 in1.6 inmuggy: 0%muggy: 0%0%0%drydrytourism score: 6.6tourism score: 6.60.10.1
St Athan Royal Air Force Base weather by month. Click on each chart for more information.

The warm season lasts for 3.1 months, from June 12 to September 15, with an average daily high temperature above 64°F. The hottest month of the year at St Athan Royal Air Force Base is July, with an average high of 68°F and low of 56°F.

The cool season lasts for 4.0 months, from November 22 to March 20, with an average daily high temperature below 50°F. The coldest month of the year at St Athan Royal Air Force Base is February, with an average low of 38°F and high of 46°F.

Average High and Low Temperature at St Athan Royal Air Force Base

Average High and Low Temperature at St Athan Royal Air Force BasewarmcoolcoolJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FFeb 1746°FFeb 1746°FAug 168°FAug 168°F38°F38°F57°F57°FJun 1264°FJun 1264°FSep 1564°FSep 1564°FNov 2250°FNov 2250°FMar 2050°FMar 2050°F52°F52°F53°F53°F42°F42°F40°F40°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°F46°F49°F54°F60°F64°F68°F67°F63°F57°F51°F47°F
Temp. 42°F42°F45°F48°F53°F58°F62°F62°F58°F53°F47°F43°F
Low 38°F38°F40°F42°F47°F52°F56°F56°F52°F48°F43°F39°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 at St Athan Royal Air Force Base

Average Hourly Temperature at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec12 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 coldcoldcoldcoolcomfortable
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.

Oak Bay, Canada (4,685 miles away) is the far-away foreign place with temperatures most similar to St Athan Royal Air Force Base (view comparison).

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At St Athan Royal Air Force Base, 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 at St Athan Royal Air Force Base begins around April 1 and lasts for 6.3 months, ending around October 11.

The clearest month of the year at St Athan Royal Air Force Base is July, during which on average the sky is clear, mostly clear, or partly cloudy 56% of the time.

The cloudier part of the year begins around October 11 and lasts for 5.7 months, ending around April 1.

The cloudiest month of the year at St Athan Royal Air Force Base is December, during which on average the sky is overcast or mostly cloudy 66% of the time.

Cloud Cover Categories at St Athan Royal Air Force Base

Cloud Cover Categories at St Athan Royal Air Force BaseclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 1657%Jul 1657%Dec 2433%Dec 2433%Apr 144%Apr 144%Oct 1145%Oct 1145%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 65%62%61%54%51%49%44%46%49%56%63%66%
Clearer 35%38%39%46%49%51%56%54%51%44%37%34%

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at St Athan Royal Air Force Base varies throughout the year.

The wetter season lasts 4.4 months, from September 21 to February 5, with a greater than 34% chance of a given day being a wet day. The month with the most wet days at St Athan Royal Air Force Base is December, with an average of 12.7 days with at least 0.04 inches of precipitation.

The drier season lasts 7.5 months, from February 5 to September 21. The month with the fewest wet days at St Athan Royal Air Force Base is April, with an average of 7.6 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 at St Athan Royal Air Force Base is December, with an average of 12.6 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 43% on December 28.

Daily Chance of Precipitation at St Athan Royal Air Force Base

Daily Chance of Precipitation at St Athan Royal Air Force BasewetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Dec 2843%Dec 2843%Apr 2224%Apr 2224%Sep 2134%Sep 2134%Feb 534%Feb 534%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 12.1d9.3d9.0d7.6d8.6d8.4d8.2d8.8d9.3d11.7d12.1d12.6d
Mixed 0.2d0.1d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.2d
Any 12.4d9.4d9.0d7.6d8.6d8.4d8.2d8.8d9.3d11.7d12.1d12.7d

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. St Athan Royal Air Force Base experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year at St Athan Royal Air Force Base. The month with the most rain at St Athan Royal Air Force Base is November, with an average rainfall of 3.2 inches.

The month with the least rain at St Athan Royal Air Force Base is April, with an average rainfall of 1.6 inches.

Average Monthly Rainfall at St Athan Royal Air Force Base

Average Monthly Rainfall at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 inOct 303.3 inOct 303.3 inApr 201.6 inApr 201.6 inDec 243.2 inDec 243.2 inJun 52.0 inJun 52.0 inJul 91.9 inJul 91.9 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 2.9″2.3″2.0″1.6″1.8″1.9″1.9″2.1″2.3″3.2″3.2″3.2″

The length of the day at St Athan Royal Air Force Base varies extremely over the course of the year. In 2024, the shortest day is December 21, with 7 hours, 51 minutes of daylight; the longest day is June 20, with 16 hours, 37 minutes of daylight.

Hours of Daylight and Twilight at St Athan Royal Air Force Base

Hours of Daylight and Twilight at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 8 minMar 2012 hr, 8 minMar 2016 hr, 37 minJun 2016 hr, 37 minJun 2012 hr, 11 minSep 2212 hr, 11 minSep 227 hr, 51 minDec 217 hr, 51 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 8.4h10.0h11.9h13.9h15.6h16.5h16.1h14.5h12.6h10.6h8.9h7.9h

The earliest sunrise is at 4:56 AM on June 15, and the latest sunrise is 3 hours, 23 minutes later at 8:18 AM on December 30. The earliest sunset is at 4:05 PM on December 12, and the latest sunset is 5 hours, 30 minutes later at 9:34 PM on June 24.

Daylight saving time (DST) is observed at St Athan Royal Air Force Base during 2024, starting in the spring on March 31, lasting 6.9 months, and ending in the fall on October 27.

Sunrise & Sunset with Twilight and Daylight Saving Time at St Athan Royal Air Force Base

Sunrise & Sunset with Twilight and Daylight Saving Time at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 154:56 AMJun 154:56 AM9:34 PMJun 249:34 PMJun 24Dec 124:05 PMDec 124:05 PM8:18 AMDec 308:18 AMDec 30Mar 31DSTMar 31DSTDSTOct 27DSTOct 27daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
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 at St Athan Royal Air Force Base

Solar Elevation and Azimuth at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec12 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 AM0000101010202030304040500001010101020203030404050601562NowNow
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 at St Athan Royal Air Force Base

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 at St Athan Royal Air Force Base, 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 at St Athan Royal Air Force Base

Humidity Comfort Levels at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Feb 250%Feb 250%Aug 90%Aug 90%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 0.0d0.0d0.0d0.0d0.0d0.0d0.1d0.1d0.0d0.0d0.0d0.0d

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 at St Athan Royal Air Force Base experiences significant seasonal variation over the course of the year.

The windier part of the year lasts for 5.5 months, from October 10 to March 24, with average wind speeds of more than 12.8 miles per hour. The windiest month of the year at St Athan Royal Air Force Base is January, with an average hourly wind speed of 14.9 miles per hour.

The calmer time of year lasts for 6.5 months, from March 24 to October 10. The calmest month of the year at St Athan Royal Air Force Base is July, with an average hourly wind speed of 10.6 miles per hour.

Average Wind Speed at St Athan Royal Air Force Base

Average Wind Speed at St Athan Royal Air Force BasewindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph5 mph5 mph10 mph10 mph15 mph15 mph20 mph20 mphJan 315.2 mphJan 315.2 mphAug 210.4 mphAug 210.4 mphOct 1012.8 mphOct 1012.8 mphMar 2412.8 mphMar 2412.8 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) 14.914.113.111.711.210.710.610.811.813.113.714.5

The predominant average hourly wind direction at St Athan Royal Air Force Base is from the west throughout the year.

Wind Direction at St Athan Royal Air Force Base

Wind Direction at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
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).

St Athan Royal Air Force Base 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 3.1 months, from July 1 to October 5, with an average temperature above 60°F. The month of the year at St Athan Royal Air Force Base with the warmest water is August, with an average temperature of 64°F.

The time of year with cooler water lasts for 4.0 months, from December 19 to April 19, with an average temperature below 49°F. The month of the year at St Athan Royal Air Force Base with the coolest water is February, with an average temperature of 45°F.

Average Water Temperature at St Athan Royal Air Force Base

Average Water Temperature at St Athan Royal Air Force BasewarmcoolJanFebMarAprMayJunJulAugSepOctNovDec40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°FAug 1464°FAug 1464°F45°FFeb 2445°FFeb 24Jul 160°FJul 160°FOct 560°FOct 560°FDec 1949°FDec 1949°FApr 1949°FApr 1949°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.
WaterJanFebMarAprMayJunJulAugSepOctNovDec
Temperature 47°F45°F46°F48°F53°F58°F62°F64°F62°F58°F53°F49°F

To characterize how pleasant the weather is at St Athan Royal Air Force Base 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 St Athan Royal Air Force Base for general outdoor tourist activities is from late June to early September, with a peak score in the last week of July.

Tourism Score at St Athan Royal Air Force Base

Tourism Score at St Athan Royal Air Force Basebest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.66.60.10.1NowNowtemperaturetemperature 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 St Athan Royal Air Force Base for hot-weather activities is from mid July to early August, with a peak score in the last week of July.

Beach/Pool Score at St Athan Royal Air Force Base

Beach/Pool Score at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec002244668810101.71.70.00.0NowNowtemperaturetemperature cloudscloudsprecipitationprecipitation
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 at St Athan Royal Air Force Base typically lasts for 8.2 months (250 days), from around March 25 to around November 30, rarely starting before February 15 or after April 22, and rarely ending before November 1 or after December 25.

Time Spent in Various Temperature Bands and the Growing Season at St Athan Royal Air Force Base

Time Spent in Various Temperature Bands and the Growing Season at St Athan Royal Air Force Basegrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Mar 2550%Mar 2550%Nov 3050%Nov 3090%Apr 2290%Apr 2290%Nov 190%Nov 110%Feb 1510%Feb 1510%Dec 2510%Dec 252%Jan 132%Jan 13Jul 25100%Jul 25100%NowNowvery coldcoldcoolcomfortable
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 at St Athan Royal Air Force Base should appear around May 8, only rarely appearing before April 26 or after May 25.

Growing Degree Days at St Athan Royal Air Force Base

Growing Degree Days at St Athan Royal Air Force BaseJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F200°F200°F400°F400°F600°F600°F800°F800°F1,000°F1,000°F1,200°F1,200°F1,400°F1,400°F1,600°F1,600°F1,800°F1,800°FMay 890°FMay 890°FAug 7900°FAug 7900°FDec 311,612°FDec 311,612°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 3.4 months, from May 2 to August 14, with an average daily incident shortwave energy per square meter above 5.3 kWh. The brightest month of the year at St Athan Royal Air Force Base is June, with an average of 6.3 kWh.

The darker period of the year lasts for 3.9 months, from October 24 to February 20, with an average daily incident shortwave energy per square meter below 1.8 kWh. The darkest month of the year at St Athan Royal Air Force Base is December, with an average of 0.7 kWh.

Average Daily Incident Shortwave Solar Energy at St Athan Royal Air Force Base

Average Daily Incident Shortwave Solar Energy at St Athan Royal Air Force BasebrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhJun 266.5 kWhJun 266.5 kWhDec 240.6 kWhDec 240.6 kWhMay 25.3 kWhMay 25.3 kWhAug 145.3 kWhAug 145.3 kWhOct 241.8 kWhOct 241.8 kWhFeb 201.8 kWhFeb 201.8 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) 0.91.62.94.55.76.36.25.23.82.21.10.7

For the purposes of this report, the geographical coordinates of St Athan Royal Air Force Base are 51.405 deg latitude, -3.436 deg longitude, and 151 ft elevation.

The topography within 2 miles of St Athan Royal Air Force Base contains only modest variations in elevation, with a maximum elevation change of 243 feet and an average elevation above sea level of 109 feet. Within 10 miles contains only modest variations in elevation (876 feet). Within 50 miles contains very significant variations in elevation (2,940 feet).

The area within 2 miles of St Athan Royal Air Force Base is covered by grassland (33%), cropland (33%), and artificial surfaces (19%), within 10 miles by water (48%) and grassland (32%), and within 50 miles by grassland (41%) and water (23%).

This report illustrates the typical weather at St Athan Royal Air Force Base, 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

St Athan Royal Air Force Base has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.

In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.

The stations on which we may fall back include but are not limited to Cardiff Airport, Exeter Airport, Bristol Airport, Chivenor, Yeovilton, Pembrey Sands, Plymouth, and Portland / Rnas.

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.