2018 London Marathon could be the hottest on record

Even London Marathon runners who’ve put months of dedicated training in ahead of the race could be caught off-guard by the soaring temperatures.

This year’s race is threatening to be the hottest on record, with the Met Office warns it will feel very warm for the runners on the capital’s streets.

Conditions may also be especially difficult for fancy-dress runners, including the almost 100 attempting Guinness World Records dressed in outfits such as a suit of armour, a Paddington Bear costume and ski boots.

Back in 1996, a highest temperature of 22.7C (72.8F) was set at the annual event, but it appears as though the record which was set 22 years ago could be under threat.

After a 29.1C (84.3F) record-breaking hottest April day for 70 years on Thursday, Met Office spokesman Grahame Madge said the mercury could rise up to 22C or 23C at weather stations in the capital on Sunday.

“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,” he said.

“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.”

Mr Madge said it is possible there could be a new warmest temperature, but stressed that even if the mercury does not exceed above the record, for runners it will feel “very, very warm”.

Tens of thousands of runners are expected to take part in the race around much of London, cheered on by thousands of supporters from the sidelines.

More water, ice and shower stations will be added along the 26.2-mile route so participants can cool down in the heat, confirmed event organisers.

Runners have been advised to consider dropping their goal times and to run more slowly, to apply suncream and to wear lightweight clothing for warmer conditions.

Mr Madge said Sunday will start off bright, with potentially some higher cloud which “may reduce the extreme glare”, but warned that later on there could be some downpours due to “increasingly humid air”.

Set to increase in intensity and frequency throughout the event, he said the showers should bring respite for participants, but may not be so enjoyable for the spectators.

Elsewhere across the weekend, a yellow warning for rain has been issued by the Met Office covering northern England and North Wales.

Heavy downpours and thunderstorms are expected to develop on Saturday afternoon and overnight into Sunday, with the warning in place from 4pm until 3am.

The Met Office warns there could be some flooding to homes and businesses, potentially loss of power from lightning strikes and poor driving conditions caused by spray from the rain water.

Along with hail and gusty winds in some places, between 15-20mm of rain may fall in a short space of time, with up to 30mm in some areas, the Met Office said.

From next week there will be cooler temperatures and a “more unsettled outlook” from Monday, Mr Madge added.