Average Weather in London United Kingdom
London has a mild humid temperate climate with warm summers and no dry season. The temperature typically varies from 39°F to 74°F over the course of the year, and is rarely below 30°F or above 84°F.
The warm season lasts for 85 days, 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 122 days, 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 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
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 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 216 days, and ending in the fall on October 29.
Sunrise & Sunset with Twilight and Daylight Saving Time
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 201 days, 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 164 days, 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.
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 254 days, 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 111 days, 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
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 in 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 and average total accumulation of 1.2 inches.
Average Monthly Rainfall
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
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 mildly seasonal variation over the course of the year.
The windier part of the year lasts for 176 days, 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 189 days, 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
The predominant average hourly wind direction in London varies throughout the year.
The wind is most often from the north for 25 days, from April 17 to May 12, with a peak percentage of 28% on April 19. The wind is most often from the west for 340 days, from May 12 to April 17, with a peak percentage of 43% on July 3.
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 very significant seasonal variation over the course of the year.
The brighter period of the year lasts for 109 days, 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 116 days, 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 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%).
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 significant variations in elevation (492 feet). Within 50 miles contains very significant variations in elevation (1,027 feet).
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 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.
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 .