BBC Weather currently forecasts rainfall in London on Monday (August 17), but predicting the weather this far ahead is always difficult and liable to change. If we do get some rain, it will come in showers and with some far more pleasant temperatures, with highs sitting around 23C. The current BBC forecast doesn't go beyond Monday August 24, so it's entirely possible that the heatwaves could make a comeback. The threshold for London is three days on the trot on which temperatures climb higher than 28C. Temperatures will likely be above average and some spells of hot weather and heatwaves are possible, especially in the south."