London is a year-round tourist centre, with few of its attractions closing or significantly reducing their opening hours in winter. Your best chance of good weather is, of course, at the height of summer in July and August, but there's certainly no guarantee of sun even in those months - plus it's when you can expect the biggest crowds and highest prices.
Many who live in London would swear that global warming has added a twist to the city's unpredictable climatic conditions. While locals used to complain about the frequent, but still somehow always unforeseen, arrival of rain, now they find themselves faced with sudden outbreaks of sunshine and dry heat instead.
Recent summers have seen record temperatures, approaching 40°C and autumns have been positively toasty. As the tube turns into the Black Hole of Calcutta and traffic fumes become choking, London is particularly ill-equipped to cope with such heat.
However, meteorologists point out that recent statistics don't yet represent anything terribly out of the ordinary for such a naturally variable climate. The average maximum temperature for July, the hottest month, is still only about 23°C. In spring and autumn temperatures drop to between 13°C and 17°C. In winter, the average daily maximum is 8°C, the overnight minimum 2°C.
Despite the appearance of snow in the past few years, it still rarely freezes in London. What weather forecasters do predict in the long-term, as a result of climate change in London, is drier summers, wetter and stormier winters and more flash floods.