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Average weather, temperature, rainfall, sunshine hours
In London, the capital of Great Britain, the climate is
influenced by the ocean and is therefore cool, humid and rainy. Atlantic fronts pass one after the other throughout the year, and bring
variable weather, with cloudiness, rains and showers, which alternate, at least in spring and summer, with a few hours of sunshine.
However, the climate is a bit milder than in the rest of Britain: the city is located in the south, and in a relatively sheltered area, called London Basin, between the Chiltern Hills to the north and the North Downs to the south. In this area, the climate is slightly warmer than in the surrounding region, except when a high pressure system arrives during winter, and causes thermal inversions and night fogs.
As happens in the big cities, in the central and most densely populated districts, the so called
urban heat island effect occurs, in fact, the temperature is slightly higher (about 2 degrees Celsius) than in the surrounding rural areas; this effect is more noticeable at night and in winter.
Precipitation amounts to 615 millimeters (24 inches) per year, and it is not as abundant as in many other European cities: the perception of London as a rainy city is mostly due to the
frequency of the rains, which can occur quite often also in summer. The rains are therefore frequent but not abundant, often light or intermittent, and usually take the form of drizzle or brief shower.
Winter, from December to February, is quite cold, with quite frequent rains, but it's not freezing, and it's much milder than the latitude suggests: the average temperature in January is about 5.5 °C (42 °F).
However, different types of weather occur. In periods of
high pressure, the temperature is low, close to freezing (0 °C or 32 °F), and the weather is cold, gray and sometimes foggy. In periods of
Atlantic currents, the temperature can be mild: up to 12/13 °C (54/55 °F) or more, with lows around 10 °C (50 °F), but the wind can blow, sometimes intensely.
When
cold currents prevail, the northern ones of polar origin, or better, the southeastern ones that come directly from the European continent, the temperature drop quite a bit, and there may be snow and frost, though usually for short periods.
Within the city,
snow accumulates with greater difficulty than in the peripheral areas, and in any case, snowfalls are rarely abundant. In February 2009, 15 cm (6 inches) of snow fell in the center and up to 30 cm (12 in) in the suburbs. In February 1991, the snow depth reached 20 cm (8 in) in the center.
In the winter months, there are approximately 6/7 days per month with minimum temperatures below freezing. On the coldest nights of the year, the temperature generally drops to -4/-5 °C (23/25 °F), but can sometimes drop to lower values. The coldest record is -13.2 °C (8.2 °F) and was set in January 1963.
In
spring, from March to May, weather disturbances still frequently pass, the average temperature slowly rises, and the first warm days alternate with the return of cold weather. In March, some snow showers may still occur; in April, the temperature can still be cold, like in winter, even though the days are much longer (the sun sets much later than in winter). Typically, the temperature becomes mild in a more stable manner by the second half of May.
Summer, from June to August, is not very warm, but in this season, the area of London is the warmest of the entire UK. In July and August, lows are around 14 °C (57 °F) and highs around 23/24 °C (73.5/75 °F). June is a bit cooler, though it is the month with the longest days.
In summer, it rains a little less than in the rest of the year: on average, one day out of three or four. On cloudy and rainy days, highs can remain about 16/17 °C (61/63 °F).
Sometimes, the London area can be reached by
hot air masses coming from Spain: in these cases, the temperature can reach 28/32 °C (82/90 °F). However, these periods are almost always short-lived because Atlantic currents usually return after a few days. Over the past few decades, heat waves are becoming more frequent due to global warming. The highest record is 40.2 °C (104.4 °F), set in July 2022. The previous record was 37.9 °C (100.2 °F), set in August 2003 and in July 2019.
In
autumn, from September to November, the temperature gradually decreases. The weather is still often pleasant in September, especially in the first half, then it gradually becomes more cold, cloudy and rainy. In November, the days are short, it's cold enough, the sun is rarely seen and the wind often blows.
In London, there are 1,675
sunshine hours per year. The sun is rarely seen from November to February, while from May to August, it shines for an acceptable number of hours, and in any case, it shines a bit more often than in the rest of Britain (excluding the southern coast).
Best Time
The best time to visit London is the summer, or more generally
from mid-May to mid-September: temperatures are generally good for outdoors activities, although it's better to bring an umbrella, and a sweatshirt or sweater for the evening or for cool days. In summer, you can hope to find a period of good weather, with warm days, during which the maximum temperature is above 25 °C (77 °F) or can even approach 30 °C (86 °F), and you can remove the outer layers of clothing, stroll in the numerous parks of the city and even sunbathe.
The following weather data was recorded at Heathrow Airport, located on the western outskirts of the city.
London - Climate data
In London, the
average temperature of the coldest month (January) is of
5.6 °C, that of the warmest month (July) is of
19 °C. Here are the average temperatures.
London - Average temperatures (1991-2020) |
| Month | Min | Max | Mean |
|---|
| January | 2.7 | 8.4 | 5.6 |
|---|
| February | 2.7 | 9.1 | 5.9 |
|---|
| March | 4.2 | 11.8 | 8 |
|---|
| April | 6 | 15.1 | 10.6 |
|---|
| May | 9.1 | 18.5 | 13.8 |
|---|
| June | 12 | 21.6 | 16.8 |
|---|
| July | 14.2 | 23.9 | 19 |
|---|
| August | 14.1 | 23.3 | 18.7 |
|---|
| September | 11.6 | 20.2 | 15.9 |
|---|
| October | 8.8 | 15.7 | 12.2 |
|---|
| November | 5.3 | 11.4 | 8.4 |
|---|
| December | 3.1 | 8.8 | 6 |
|---|
| Year | 7.8 | 15.7 | 11.75 |
|---|
amounts to
615 millimeters per year: so, it is at an intermediate level. It ranges from
40 millimeters in the driest months (March, April) to
65 millimeters in the wettest ones (October, November) Here is the average precipitation.
London - Average precipitation| Month | Days |
|---|
| January | 60 | 12 |
|---|
| February | 45 | 10 |
|---|
| March | 40 | 8 |
|---|
| April | 40 | 9 |
|---|
| May | 45 | 8 |
|---|
| June | 45 | 8 |
|---|
| July | 45 | 8 |
|---|
| August | 55 | 8 |
|---|
| September | 50 | 8 |
|---|
| October | 65 | 11 |
|---|
| November | 65 | 11 |
|---|
| December | 55 | 11 |
|---|
| Year | 615 | 112 |
|---|
There are on average around 1675
sunshine hours per year. Here are the average hours of sunshine per day.
London - Sunshine hours| Month | Average | Total |
|---|
| January | 2 | 60 |
|---|
| February | 3 | 80 |
|---|
| March | 4 | 125 |
|---|
| April | 6 | 175 |
|---|
| May | 6.5 | 210 |
|---|
| June | 7 | 210 |
|---|
| July | 7 | 220 |
|---|
| August | 6.5 | 200 |
|---|
| September | 5 | 155 |
|---|
| October | 3.5 | 115 |
|---|
| November | 2.5 | 70 |
|---|
| December | 2 | 55 |
|---|
| Year | 4.6 | 1675 |
|---|
London - Weather by month
Based on the period 1991-2020
January, the coldest month of the year, is generally a quite cold month. The average temperature is of
5.6 °C, with a minimum of
2.7 °C and a maximum of
8.4 °C.
On the coldest nights of the month, the temperature usually drops to around
-3.5 °C. However, it dropped to
-6.8 °C in January 2009.
On the warmest days of the month, the temperature usually reaches around
13.5 °C. However, it reached
15.4 °C in January 1999.
Precipitation amounts to
60 mm, distributed over 12 days.
The day lasts on average 8 hours and 25 minutes.
There are on average 2 hours of sunshine per day. So, the sun shines 23% of the time.
The average humidity is 83%. Hence, the air is normally humid.
The average wind speed is of
15.6 kph.
February is generally a quite cold month. The average temperature is of
5.9 °C, with a minimum of
2.7 °C and a maximum of
9.1 °C.
On the coldest nights of the month, the temperature usually drops to around
-3.5 °C. However, it dropped to
-8.9 °C in February 1991.
On the warmest days of the month, the temperature usually reaches around
14.5 °C. However, it reached
20.1 °C in February 2019.
Precipitation amounts to
45 mm, distributed over 10 days.
The day lasts on average 10 hours and 0 minutes.
There are on average 3 hours of sunshine per day. So, the sun shines 28% of the time.
The average humidity is 79%. Hence, the air is normally humid.
The average wind speed is of
15.1 kph.
March is generally a quite mild month. The average temperature is of
8 °C, with a minimum of
4.2 °C and a maximum of
11.8 °C.
On the coldest nights of the month, the temperature usually drops to around
-1.5 °C. However, it dropped to
-5.1 °C in March 2018.
On the warmest days of the month, the temperature usually reaches around
18 °C. However, it reached
22.8 °C in March 2012.
Precipitation amounts to
40 mm, distributed over 8 days.
The day lasts on average 12 hours and 0 minutes.
There are on average 4 hours of sunshine per day. So, the sun shines 33% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is of
14.7 kph.
April is generally a mild month. The average temperature is of
10.6 °C, with a minimum of
6 °C and a maximum of
15.1 °C.
On the coldest nights of the month, the temperature usually drops to around
0.5 °C. However, it dropped to
-1.6 °C in April 1999.
On the warmest days of the month, the temperature usually reaches around
22 °C. However, it reached
28.5 °C in April 2018.
Precipitation amounts to
40 mm, distributed over 9 days.
The day lasts on average 14 hours and 0 minutes.
There are on average 6 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 70%.
The average wind speed is of
13.5 kph.
May is generally a mild month. The average temperature is of
13.8 °C, with a minimum of
9.1 °C and a maximum of
18.5 °C.
On the coldest nights of the month, the temperature usually drops to around
3.5 °C. However, it dropped to
-0.5 °C in May 1997.
On the warmest days of the month, the temperature usually reaches around
26.5 °C. However, it reached
30.7 °C in May 2005.
Precipitation amounts to
45 mm, distributed over 8 days.
The day lasts on average 15 hours and 40 minutes. So the days are long.
There are on average 6.5 hours of sunshine per day. So, the sun shines 43% of the time.
The average humidity is 68%.
The average wind speed is of
13.5 kph.
June is generally a very mild month. The average temperature is of
16.8 °C, with a minimum of
12 °C and a maximum of
21.6 °C.
On the coldest nights of the month, the temperature usually drops to around
7.5 °C. However, it dropped to
2.9 °C in June 1991.
On the warmest days of the month, the temperature usually reaches around
29.5 °C. However, it reached
34 °C in June 2019.
Precipitation amounts to
45 mm, distributed over 8 days.
The day lasts on average 16 hours and 35 minutes. So the days are long. June 21, the summer solstice, is the longest day of the year in the Northern Hemisphere.
There are on average 7 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 67%.
The average wind speed is of
13.6 kph.
July, the warmest month of the year, is generally a warm month. The average temperature is of
19 °C, with a minimum of
14.2 °C and a maximum of
23.9 °C.
On the coldest nights of the month, the temperature usually drops to around
10 °C. However, it dropped to
6.7 °C in July 1993.
On the warmest days of the month, the temperature usually reaches around
31 °C. However, it reached
37.9 °C in July 2019.
Precipitation amounts to
45 mm, distributed over 8 days.
The day lasts on average 16 hours and 5 minutes. So the days are long.
There are on average 7 hours of sunshine per day. So, the sun shines 44% of the time.
The average humidity is 66%.
The average wind speed is of
13.6 kph.
August is generally a warm month. The average temperature is of
18.7 °C, with a minimum of
14.1 °C and a maximum of
23.3 °C.
On the coldest nights of the month, the temperature usually drops to around
9 °C. However, it dropped to
5.9 °C in August 2012.
On the warmest days of the month, the temperature usually reaches around
30.5 °C. However, it reached
37.9 °C in August 2003.
Precipitation amounts to
55 mm, distributed over 8 days.
The day lasts on average 14 hours and 30 minutes. So the days are long.
There are on average 6.5 hours of sunshine per day. So, the sun shines 45% of the time.
The average humidity is 69%.
The average wind speed is of
13.1 kph.
September is generally a very mild month. The average temperature is of
15.9 °C, with a minimum of
11.6 °C and a maximum of
20.2 °C.
On the coldest nights of the month, the temperature usually drops to around
6.5 °C. However, it dropped to
3.3 °C in September 2018.
On the warmest days of the month, the temperature usually reaches around
26 °C. However, it reached
32.9 °C in September 2016.
Precipitation amounts to
50 mm, distributed over 8 days.
The day lasts on average 12 hours and 35 minutes.
There are on average 5 hours of sunshine per day. So, the sun shines 42% of the time.
The average humidity is 74%. Hence, the air is normally humid.
The average wind speed is of
12.8 kph.
October is generally a mild month. The average temperature is of
12.2 °C, with a minimum of
8.8 °C and a maximum of
15.7 °C.
On the coldest nights of the month, the temperature usually drops to around
2.5 °C. However, it dropped to
-2.5 °C in October 1997.
On the warmest days of the month, the temperature usually reaches around
21 °C. However, it reached
28.3 °C in October 2011.
Precipitation amounts to
65 mm, distributed over 11 days.
The day lasts on average 10 hours and 35 minutes.
There are on average 3.5 hours of sunshine per day. So, the sun shines 35% of the time.
The average humidity is 80%. Hence, the air is normally humid.
The average wind speed is of
13.5 kph.
November is generally a quite mild month. The average temperature is of
8.4 °C, with a minimum of
5.3 °C and a maximum of
11.4 °C.
On the coldest nights of the month, the temperature usually drops to around
-1.5 °C. However, it dropped to
-5.8 °C in November 1993.
On the warmest days of the month, the temperature usually reaches around
16.5 °C. However, it reached
18.5 °C in November 2010.
Precipitation amounts to
65 mm, distributed over 11 days.
The day lasts on average 8 hours and 50 minutes.
There are on average 2.5 hours of sunshine per day. So, the sun shines 27% of the time.
The average humidity is 84%. Hence, the air is normally humid.
The average wind speed is of
13.2 kph.
December is generally a quite cold month. The average temperature is of
6 °C, with a minimum of
3.1 °C and a maximum of
8.8 °C.
On the coldest nights of the month, the temperature usually drops to around
-3.5 °C. However, it dropped to
-9.4 °C in December 2010.
On the warmest days of the month, the temperature usually reaches around
14 °C. However, it reached
16.4 °C in December 2015.
Precipitation amounts to
55 mm, distributed over 11 days.
The day lasts on average 7 hours and 55 minutes. So the days are short. December 21, the winter solstice, is the shortest day of the year in the Northern Hemisphere.
There are on average 2 hours of sunshine per day. So, the sun shines 22% of the time.
The average humidity is 85%. Hence, the air is normally humid.
The average wind speed is of
14.6 kph.