Weather in London in December

A hard month. December asks something of you. Go in knowing what. Highs sit at 7.7 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

December ranks 11 of 12 — near the bottom of London's year. September is the month that works, and the swing between the two is 49 points, which is a different holiday rather than a slightly better one.

Rain on 13 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at 7.7 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 7 nights fall below freezing; the day barely swings — 5 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest December day reached 14.3 °C and the coldest night fell to -5.6 °C.

December is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest December on record still delivered 125 mm against 20 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 71 mm average is a reasonable planning figure, not a promise.

Wind is light at 13.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 94%, which at 7.7 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How December sits in the year

Temperatures hold steady either side: 10.8 °C in November, 7.7 here, 7.2 in January. Nothing about the timing within the month matters much.

Daylight in December

December sits at the dark end of London's year — 7.9 hours of daylight against 16.6 at midsummer, losing 0.4 hours across the month. Sightseeing days are genuinely shorter, and an itinerary built for summer will not fit.

An inland climate

Despite being inland, the year stays fairly even: 21.1 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

December in London versus nearby

If London is one option among several, the nearby comparison is worth making. Birmingham is close enough to be a coin toss — within a degree on temperature, 1 day more rain. Le Havre is close enough to be a coin toss — within a degree on temperature, 3 days more rain.

So: December is a compromise. September is 46 points better and is what London is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in London

See all twelve months in London, or where else to go in December.