Sunny weather in London is "very unlikely" during the Olympic Games which begin later this month, forecasters said after the wettest June on record in Britain.
Britain's Met Office predicted slightly better conditions for the month ahead than in recent weeks when torrential rains triggered severe flooding in parts of the country.
But forecasters said "below average sunshine" and temperatures are expected during the London 2012 Games which run from July 27 to August 12.
"Climatologically this is the warmest part of the year, but this year a protracted spell of hot, sunny weather looks very unlikely," the Met Office said in its 30-day outlook.
"In fact the inclement weather that has characterised June and early July will probably still be in evidence, although overall conditions are unlikely to be as bad."
Very wet conditions in southern England were more probable than dry ones, the Met Office warned, while stressing that the outlook for rainfall remained "extremely uncertain".
The forecast comes as heavy rains continue to hit large swathes of Britain where authorities issued more than 150 flood alerts and warnings on Sunday.
A man in his early 20s was killed in Northumberland, in northeast England, on Saturday after his car crashed on a rain-drenched road.
Meanwhile at the British Grand Prix at Silverstone 25,000 spectators were told to go home on Saturday because of flooded car parks.
Britain experienced double the average amount of rainfall last month, making it the wettest June since records began in 1910, the Met Office said.
The period from April to June was also the wettest recorded.
Celebrations for Queen Elizabeth II's diamond jubilee were marred by the inclement weather in early June but millions of Britons turned out regardless to mark her 60 years on the throne.