The current record for the marathon is 22.7C (72.8F) in 1996 but the Met Office said temperatures at this year’s event on Sunday could reach 23C (73.4F) at some weather stations in the capital.
Met Office spokesman Grahame Madge said But a big caveat here is obviously a weather station temperature record will feel a bit different to what it might feel like trackside where you have the warmth coming up from the tarmac and other people.
Trackside temperatures will probably feel even warmer than that, so the advice to runners is to look at the forecast and prepare for the fact that this could be one of the warmer marathons.
The Met Office issued yellow warnings for rain across East Midlands, North East and North West England and parts of Yorkshire and Humberside and Wales overnight, where flooding was expected after heavy showers.
Londoners were also kept up by thunderstorms and showers, following a humid day, with fresh and cloudy conditions at sunrise on Sunday.
But conditions are expected to become warmer and sunnier by the time the marathon gets underway.
Sky Weather Presenter Jo Edwards said We’ve seen temperatures close to 30C (86F) this week, and plenty of sunshine too, but thunderstorms breaking out across the country herald a change in the weather.
In reality it’s the frontal system crossing the country west to east that will bring cooler, more changeable conditions from Monday onwards.
The South East is likely to have another warm and sunny day on Sunday.
Those attempting the London Marathon have been advised to rethink fancy dress and to stay hydrated, especially as full sunshine is predicted, prompting concerns about heat.
Organisers of the event said they had emailed runners to warn them they needed to take the conditions into account in their race plans.
Hugh Brasher, event director, said in a statement We have reminded them that they should adjust their goal for Sunday and plan to run at a slower pace and, if they were planning to run in fancy dress, they should think carefully if that is appropriate in these conditions.
There is plenty of water available and runners should drink according to their thirst and use spare water to douse their head and neck.
This year’s #LondonMarathon is set to be one of the warmest on record. Dry and sunny through the morning but with an increasing shower risk through the afternoon. Good luck to all the runners! pic.twitter.com/tWh5SgKgcx
Race organisers added they would be putting more water, ice and shower stations along the 26.2-mile route so participants can cool down in the heat.
On Thursday, the UK enjoyed its hottest April day for 70 years when the mercury reached 29.1C (84.4F) in the capital.
On Friday, temperatures were a little lower but still made 26.1C (79F) in London’s St James’s Park – more than 10C above the April average – and it was at least 24C (75F) in London on Saturday.
Forecasters said that the temperatures were not expected to be as hot in the coming days as they were last week but it would still be warm for the time of year.
It is expected to be mainly dry and fine on Monday with outbreaks of rain on Tuesday and showers on Wednesday, with temperatures a little above average, according to the Met Office.
News Source SkyNews