London weather in July

I was in London in July and found many trains had spare capcity on the underground system. Be careful of drawing conclusions in European cities in August when many locals disappear off on vacation.

Regulars are candid that recent early-September stretches have run warm and sunny, but are careful to add that's no guarantee for any given year - the month can just as easily turn wet, windy and chilly. Our row backs the moderate average sitting between those extremes, 20.7C over 12.3C nights, with 56.2mm of rain across 10.6 days. Regulars picked this month specifically expecting lighter crowds than July or August alongside reasonably decent weather, and are consistent that layering plus an umbrella and cardigan for cooler evenings is the standard advice regardless of how the daytime weather turns out. The record: humidity 78 percent, 7.8 hours of sun, a 19 kph wind and AQI 46.

Asked what to pack for late May, regulars give the only honest English answer: wet, dry, chilly, warm and sunny are all possible, so the list is layers, a light waterproof and shoes that will take five or six miles a day on uneven ground. Our row lands mild rather than warm - 18.9C reading as 17C in an 18.3 kph wind, over 9.8C nights - with 53.4mm of rain across 10 days, which is a shower every third day rather than a wet month. What May really offers is length: 15.6 hours of daylight with 10.5 of sun. The gardens are the reason people come now, and the last week of the month is also the dearest. The record: humidity 74 percent, a dew point of 7.8C and AQI 46.

London-forum threads on August are candid that it's the year's peak for crowds - school holidays fill the museums and attractions with families - though several posters note the weather itself runs milder than June or July, without June's harder sun. The catch more than one mentions: much of the city, from shops to older hotels, still doesn't have air conditioning, so a warm spell is felt more than the numbers alone suggest. August's record: 23.7C days, 14.8C nights, 53mm of rain across nine and a half days, 9.7 hours of sun and a clean AQI of 41 - comfortable weather, uncomfortable queues.

London regulars are unanimous that January is “cold and, at times, wet” rather than dramatic — expect “0°C and 10°C,” “damp, grey weather rather than freezing cold,” and snow that “never falls properly... when it does, it's over within hours.” The advice is layering over a full parka: warm coat, hat, scarf, gloves, with snow boots only needed if a forecast actually predicts sub-zero days. The upside forum posters keep repeating: attractions stay open, queues vanish, and hotel prices drop. Our record matches the “cold, not brutal” read: 7.4°C days, 1.7°C nights, 10.6 rain days and just 1.7cm of snow for the month.