People with tickets to outdoor Olympics events should wear wellies, organisers said today, as they admitted the enduring bout of wet weather was “proving quite a challenge” for the Games.
Heavy rainfall has left sports sites waterlogged, with particular problems at watersports and equestrian venues Eton Dorney and Greenwich Park.
Speaking at the first daily press conference at the Olympic Park in Stratford, east London, London 2012 chairman Lord Coe said trackways and temporary surfaces were being laid down for vehicles and pedestrians to travel across while additional shelters were being built for workers at the affected sites.
Contingencies were also in place for some events such as rowing and equestrian sports which have extra days available to them in case they are rained off, he said.
He added: "That is the last resort of course.
"We have got an alternative sailing course available to us in Weymouth and we have of course got the famous roof at Wimbledon.
"Then for those hardy souls that normally reside in track and field, hockey and triathlon, it is pretty much business as usual."
Lord Coe told reporters: "This is a challenge. I have joked in the past about putting a roof across the whole country.
"But let's be clear, this is actually proving quite a challenge to us.
"At the risk of sounding a little bit like a father about to issue their kids off an Outward Bound trip, let me make the obvious point that we are a northern European country.
"People do need to be wearing the right footwear, the right rain-proof clothing and sun screen."
But he added that the Olympics were still on schedule and the cost of the wet weather was included in the overall contingency budget for the Games.
The wettest period of April to June on record, followed by more heavy rain so far this month, has caused widespread - and in some cases, repeated - flooding in many areas of the country.
Forecasters said it was too early to say what the weather would be like during the Games, although there was a "glimmer of hope" that it may brighten up.
Julian Mayes, forecaster at the MeteoGroup, the weather division of the Press Association, said: "There is a glimmer of hope that the main depression track, which has been the source of the rain we have experienced, is beginning to move north now, so we are expecting to see better weather in south-east England.
"It is a slow change and we will have to wait until next week to see how it plays out, but the fact that it is a slow improvement gives us confidence the weather might be better for the start of the Olympics."
Mr Mayes said that despite expectations of "drier, warmer and brighter" conditions during the first week of the Games it is too early to say whether London would be spared rain on the night of the Olympics opening ceremony.
He also warned that Olympic venues north of London would not benefit from the rain track's gradual move northwards.
Met Office figures released today showed that the UK has already had more than the average rainfall in July than would be expected for the whole month.
Its provisional mid-month statistics recorded 71.8mm of rain falling up to the 15th of the month.
And so far the country has seen just a quarter (26%) of the average amount of sunshine for the whole month, making the summer a very dull one so far. The average temperature has been 13.7C, which is 1.1C lower than the monthly average.
A Met Office spokesman added: "While more rain is expected in parts of the UK today there will also be some dry and sunny weather too.
"The good news is that the weekend is set to bring drier and brighter weather to many parts of England and Wales - while the far north-west of Scotland is likely to see some much-needed rain."
For those wanting to take a punt on the weather during the Games, Coral bookmakers has offered odds of 2/1 of rain falling in the Olympic Stadium during the men's 100m final and 25/1 on adverse weather forcing the cancellation of a full day's athletics.
Ladbrokes is offering odds of 6/4 that rain falls at the opening ceremony on July 27.