There's elements of what the housing is designed for too. I'm not sure what the common building materials are there but many houses in the UK are built of brick and not designed for airflow at all. Parts of London hit 38 degrees at one point last year.
Lisbon is right at the Atlantic coast. Do the summers get that hot there? Inland places get more extreme weather, both cold and hot.
Fun fact, according to Windy[0], Lisbon has 21°C right now, while eg Murmansk has 29°C.
I live in Lisbon. Most people don't have AC at home, we survive.