Weather in London

London is in United Kingdom at 51.5°N. The 2001–2020 NASA POWER daily record describes a mild oceanic climate. Rain is about 709 mm of rain spread through the year. The wettest month is October at 74 mm; the driest is April at 42 mm.

July is the warmest month (average 17.5°C, high 22.5°C) and January is the coolest (average 4.2°C, low 1.6°C). From the coolest night in January (1.4°C) to the hottest afternoon in July (22.5°C), the raw range is 21.1°C. On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are July, August, and September.

Rainfall pattern

Annual rainfall is 709 mm. October leads at 74 mm; April is lightest at 42 mm.

A rainy day here is a day with at least 1 mm in the NASA POWER series. October averages 14 such days; April averages 11.

Hot and cool months in London

Monthly average highs run from 6.9°C in January to 22.5°C in July. Nights follow the same curve: 1.6°C in January and 12.5°C in July.

Mean high across all twelve months is 14.5°C and mean low is 6.4°C. These are 20-year grid averages, so a city station can read a few degrees warmer or cooler.

What stands out month by month

January is the coolest month, with lows around 1.6°C and highs near 6.9°C. Rainfall is 65 mm. April is the driest month, averaging only 42 mm across 11 rainy days. Highs sit near 13.9°C. Peak heat arrives in July: 22.5°C by day, 12.5°C at night, and 76% humidity.

October is the wettest month — 74 mm and 14 rainy days, with 87% humidity. November: 10.5°C high, 4.5°C low, 74 mm rain, 92% humidity.

Best months to visit London

The three months with the highest comfort score are July, August, and September: July (17.5°C average, 60 mm, 76% humidity); August (17.4°C average, 66 mm, 78% humidity); September (14.9°C average, 44 mm, 81% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you prefer the hottest stretch, that is July. The coolest stretch is January.

How London compares inside United Kingdom

London is the only United Kingdom city in this dataset, so the figures on this page are the national sample we publish. They still come from the same NASA POWER daily series (2001–2020) used everywhere else on the site.