It’s always time to visit London. Even though it’s approximately at the same latitude of Edmonton, Alberta, weather patterns keep the environment from being extreme. It gets cold in the winter, but rarely snowed in. It gets warm in the summer, but rarely blisteringly so (in fact, most buildings don’t even have air-conditioning). The winter months are generally more humid than the summer ones, but experience only slightly more rain. Locals use the free, reliable Met Office Weather app, by the U.K.’s national weather service, to pinpoint forecasts by GPS.
You don't come to London for the weather. Yes, it rains, but nowhere near as much as Britain's reputation suggests. Downpours are most likely in the Autumn, especially November (2 1/2 in./63mm. on average). It can, however, rain at any time; there's no "dry season" here. Daytime temperatures can range from -1° to 35°C (30° to 95°F), but they rarely stay below 2°C (36°F) or above 26°C (79°F) for too long. Evenings are usually cool, even in summer, but hot July and August days can be muggy -- particularly on the Underground, which is not air-conditioned. Note that the British like to keep hotel thermostats about 6°C (10°F) below the American comfort level.
The principal art season (for theater, concerts, art shows) falls between September and May, leaving the summer months for festivals and park-going. A few royal attractions, such as the state rooms of Buckingham Palace, are only open in the summer when the Queen decamps to Scotland. In summer, when the weather is warmest, the sun sets after 10pm, and half of Europe takes its annual holiday, the airfares are higher, as are hotel rates, and the queues for most of the tourist attractions, such as the London Eye and the Tower of London, might make you wish you’d come in March. For decent prices and lighter crowds, go in spring or fall—April and October seem to have the best confluence of mild weather, pretty plantings, and tolerable crowds. Prices are lowest in mid-winter, but a number of minor sights, such as historic houses, sometimes close from November to March, and the biggest annual events take place during the warmer months.
When You'll Find Bargains
The cheapest time to fly to London is usually during the off season: from late October to mid-December and from January to mid-March. In the last few years, long-haul airlines in particular have offered some irresistible fares during these periods. Remember that weekday flights are often cheaper than weekend fares.
Rates generally increase between March and June, and hit their peak in high travel seasons between late June and September, and in December for the run-up to Christmas and New Year. July and August are also when most Europeans take their holidays, and so as well as higher prices you have to deal with more crowds and limited availability of the best hotel rooms.
You can avoid crowds to some extent, by planning trips for November or January through March. Sure, it may be rainy and cold -- but London doesn't shut down when the tourists thin out a little! In fact, it's a 365-days-a-year tourism city, and the winter season includes some of London's best theatre, opera, ballet, and classical music offerings. Additionally, hotel prices can drop by 20% (unheard of during peak travel times). By arriving after the winter holidays, you can also take advantage of post-Christmas sales, which these days start as early as December 26 or 27. There's usually another major sales period in stores in midsummer.
England observes eight public holidays (also known as "bank holidays") spread throughout the year: New Year's Day (January 1); Good Friday and Easter Monday (usually April); May Bank Holiday (first Monday in May); Spring Bank Holiday (usually last Monday in May, but occasionally the first in June); August Bank Holiday (last Monday in August); Christmas Day (December 25); Boxing Day (December 26). If a marked date such as Christmas Day falls on a Saturday or Sunday, the public holiday rolls over to the following Monday.
London’s Average Daytime Temperatures & Rainfall
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Temp. ([dg]F) 39 39 43 46 52 58 62 62 57 51 44 42
Temp. ([dg]C) 3 3 6 7 11 14 16 16 13 10 6 5
Rainfall (in.) 3.1 2 2.4 2.1 2.2 2.2 1.8 2.2 2.7 2.9 3.1 3.1
Rainfall (mm) 49 39 40 43 47 52 59 57 56 62 59 53
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.