The clouds currently surrounding London are expected to stay around during the early afternoon but there are likely to be sunny spells as the day continues.
The early evening could be bright for the athletics session beginning at 6pm.
Temperature-wise, the clouds will keep the air feeling muggy in London, with highs of 22 degrees barely dropping even into the evening.
There are rain showers surrounding Weymouth early this afternoon, but the worst of the rain could avoid the sailing competitions.