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Average Weather in London United Kingdom

In London, the summers are short, comfortable, and partly cloudy and the winters are long, chilly, windy, and mostly cloudy. Over the course of the year, the temperature typically varies from 39°F to 74°F and is rarely below 30°F or above 84°F.

The warm season lasts for 2.8 months, from June 14 to September 7, with an average daily high temperature above 68°F. The hottest day of the year is August 1, with an average high of 74°F and low of 60°F.

The cool season lasts for 4.1 months, from November 16 to March 18, with an average daily high temperature below 53°F. The coldest day of the year is February 7, with an average low of 39°F and high of 47°F.

Average High and Low Temperature

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.

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

Average Hourly Temperature in LondonJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMcoldcoolchillycomfortable
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 45°F < cold < 55°F < cool < 65°F < comfortable < 75°F < warm < 85°F < hot < 95°F < sweltering. The shaded overlays indicate night and civil twilight.

Clouds

In London, 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 London begins around April 2 and lasts for 6.6 months, ending around October 20. On July 15, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 58% of the time, and overcast or mostly cloudy 42% of the time.

The cloudier part of the year begins around October 20 and lasts for 5.4 months, ending around April 2. On December 27, the cloudiest day of the year, the sky is overcast or mostly cloudy 74% of the time, and clear, mostly clear, or partly cloudy 26% of the time.

Cloud Cover Categories

Cloud Cover Categories in LondonclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 1558%Jul 1558%Dec 2726%Dec 2726%Apr 242%Apr 242%Oct 2042%Oct 2042%partly cloudymostly cloudyclearovercastmostly clear
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

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

The wetter season lasts 8.2 months, from May 27 to February 5, with a greater than 26% chance of a given day being a wet day. The chance of a wet day peaks at 32% on December 30.

The drier season lasts 3.7 months, from February 5 to May 27. The smallest chance of a wet day is 20% on April 28.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 32% on December 30.

Daily Chance of Precipitation

Daily Chance of Precipitation in LondonwetwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Dec 3032%Dec 3032%Apr 2820%Apr 2820%Feb 526%Feb 526%rain
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).

Rainfall

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. London experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in London. The most rain falls during the 31 days centered around October 21, with an average total accumulation of 2.2 inches.

The least rain falls around March 12, with an average total accumulation of 1.2 inches.

Average Monthly Rainfall

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 liquid-equivalent snowfall.

Sun

The length of the day in London varies extremely over the course of the year. In 2017, the shortest day is December 21, with 7 hours, 50 minutes of daylight; the longest day is June 21, with 16 hours, 38 minutes of daylight.

Hours of Daylight and Twilight

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.

The earliest sunrise is at 4:42 AM on June 17, and the latest sunrise is 3 hours, 24 minutes later at 8:06 AM on December 30. The earliest sunset is at 3:51 PM on December 12, and the latest sunset is 5 hours, 31 minutes later at 9:21 PM on June 24.

Daylight saving time (DST) is observed in London during 2017, starting in the spring on March 26, lasting 7.1 months, and ending in the fall on October 29.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in LondonJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 174:42 AMJun 174:42 AM9:21 PMJun 249:21 PMJun 24Dec 123:51 PMDec 123:51 PM8:06 AMDec 308:06 AMDec 30Mar 26DSTMar 26DSTDSTOct 29DSTOct 29daynightnightnightnight
The solar day over the course of the year 2017. 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.

Humidity

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 London, 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

Humidity Comfort Levels in LondonJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jan 270%Jan 270%Aug 130%Aug 130%drydrycomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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

The windier part of the year lasts for 5.8 months, from October 12 to April 6, with average wind speeds of more than 6.1 miles per hour. The windiest day of the year is January 3, with an average hourly wind speed of 7.2 miles per hour.

The calmer time of year lasts for 6.2 months, from April 6 to October 12. The calmest day of the year is August 3, with an average hourly wind speed of 5.2 miles per hour.

Average Wind Speed

Average Wind Speed in LondonwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph10 mph11 mph12 mphJan 37.2 mphJan 37.2 mphAug 35.2 mphAug 35.2 mphOct 126.2 mphOct 126.2 mphApr 66.1 mphApr 66.1 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

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

The wind is most often from the north for 3.6 weeks, from April 17 to May 12, with a peak percentage of 28% on April 19. The wind is most often from the west for 11 months, from May 12 to April 17, with a peak percentage of 40% on January 1.

Wind Direction

Wind Direction in LondonWNWJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%northwestsoutheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Solar Energy

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 1 to August 18, with an average daily incident shortwave energy per square meter above 5.2 kWh. The brightest day of the year is June 28, with an average of 6.4 kWh.

The darker period of the year lasts for 3.8 months, from October 26 to February 19, with an average daily incident shortwave energy per square meter below 1.8 kWh. The darkest day of the year is December 26, with an average of 0.6 kWh.

Average Daily Incident Shortwave Solar Energy

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of London are 51.509 deg latitude, -0.126 deg longitude, and 66 ft elevation.

The topography within 2 miles of London contains only modest variations in elevation, with a maximum elevation change of 164 feet and an average elevation above sea level of 70 feet. Within 10 miles contains only modest variations in elevation (492 feet). Within 50 miles contains significant variations in elevation (1,027 feet).

The area within 2 miles of London is covered by artificial surfaces (96%), within 10 miles by artificial surfaces (97%), and within 50 miles by cropland (40%) and grassland (26%).

Data Sources

This report illustrates the typical weather in London, 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 London.

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

The stations contributing to this reconstruction are: London Weather Centre (97%, 1.1 kilometers, southeast) and RAF Northolt (3.3%, 21 kilometers, west).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.