Heatwave: Why is it so hot?

Temperatures are expected to rise across the UK this week.

Forecasters think in the south-east of England they could reach up to 35 degrees.

The Met Office has even said we could see the hottest day on record.

The current record for July is from 2015 when it reached 36.7C in Heathrow, but it could get even hotter and beat 38.5C which was set in Faversham, Kent, in August 2003.

BBC weather presenter Simon King explains why we're having a heatwave.