With temperatures expected to reach the high 20s over the weekend, bookmakers have slashed their odds on this August being the hottest on record in the UK.
Coral has cut its odds from 3-1 to 2-1, and the firm has seen a flurry of money being bet on this month beating previous highs.
The bookmaker also has odds of 8-1 for the UK to have the hottest year on record.
John Hill, from the firm, said: "Before the month got under way, August was well backed to be the hottest on record as punters were banking on a heatwave.
"Following another flurry of bets, we are now starting to sweat over this gamble being landed, as temperatures are set to rise once again over the weekend."