When it is genuinely hot, Poole’s problem stops being the weather and becomes the car parks.
Arrive early or do not drive
Beach car parks at Sandbanks and the chines fill by mid-morning on a hot day. The bus from town is routinely faster door to door. Better still, come by train and skip it entirely.
Pick the right beach
Branksome Dene and Hamworthy Park over Sandbanks. Same sea, fraction of the people.
Find the shade
The chines are wooded valleys cutting down the cliff to the sand, and they are several degrees cooler than the beach. Upton Country Park and the woodland on Brownsea Island do the same job.
Get on the water
A sheltered, shallow harbour on a hot day is the best place in Poole to be. See watersports and boat trips.
Stay safe
Swim between the flags where lifeguards are on duty. Do not swim in the harbour entrance. Watch inflatables in an offshore breeze: it is the commonest cause of rescues on this coast. And heathland is tinder-dry in a heatwave, so no fires or disposable barbecues anywhere near it. See beach safety.