how do people in london uk sleep cool in the summer?

Actually, it's not only in London. The same is in Ukraine where not every family has AC. We open windows to let cool air from outside get into the apartment/house. Cold showers do help a lot, and sometimes we don't cover ourselves with any sheet.

We open our windows and internal doors, use fans or have cool showers before bed and only have a thin cotton sheet over our bodies.

We open windows. Maybe turn on fans.

Sash windows, when used properly (open top & bottom) create air circulation.

We open our bedroom windows or put a fan on our bedside table.

On very hot nights if the windows being open doesn't help, I take an Ice Pack from the freezer, wrap it in a tea-towel and hug it like an anti-hot water bottle.

Open windows, fans

Open the window if necessary. My house is Victorian and because the walls are thick and the ceilings high it rarely gets too hot. Some houses (eg in Saudi Kensington) do have air conditioning but they are usually noisy and more trouble than they are worth for the odd night that does get sweltering. The rest of us resort to a stiff nightcap.

It Rarely gets Hot in London 35 degrees C during the day is NOT hot

44 degrees c at Mid afternoon is Hot

I love the Moderate English Summers

I Now live in Australia and always go on holiday in Europe at Summertime because it is so cool

With a fan or they open up their windows. 

The further north it is, the cooler the temperature. 

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