A 13-year-old boy died after getting into difficulty in a West Yorkshire reservoir on Bank Holiday Monday, police said.
The West Yorkshire force was called to Leadbeater Dam on Lumb Lane, Halifax, just before 3.20pm.
A spokesperson said the teenage boy was pulled from the water and taken to hospital, where he was pronounced dead.
Calderdale CID are investigating but said there are not believed to be any suspicious circumstances.
The incident came after the UK recorded its hottest May day since Met Office data began, the forecaster said.
The country also recorded its provisional all-time hottest meteorological spring temperature when Kew Gardens in south-west London hit 34.8C on Monday.
Meanwhile, the hottest May temperature could be broken again on Tuesday with an expected high of 35C across large swathes of southern England and Wales – which could even creep up to 36C, the Met Office said.
Those forecasts span the Midlands, the south-east and south-west of England, East Anglia and South Wales.
