Unfortunately, high temperatures are expected to return today with a forecast high of 26 degrees and probably still no rain. But we have better news for the weekend with heavy rain promised for Saturday, so you are likely to get a chance to use your umbrellas and other London type gear.

http://www.bbc.co.uk/weather/2643743

Most Wikimanians will be spending most of the day indoors, except of course for smokers. The organisers of the cricket match have found a covered venue for  Saturday night's match, so neither rain nor lightning should be a problem. https://wikimania2014.wikimedia.org/wiki/England_vs_Rest_of_the_World_Rapid_Cricket_match