Do now
- Move to the coolest room in the house: lowest floor, north-facing if you have one.
- Shut the windows and put the blinds down for the day.
- Start wet-cloth evaporative cooling.
Then
- Keep a siesta schedule: rest through the hottest part of the day.
- Open everything back up once it is cool at night.
- Keep salt and water (ORS) discipline.
Never
Never skip checking on elderly neighbours, twice daily. In most countries, heat kills more people than storms do.