Where I live in the Dordogne in France houses (and outbuildings) are traditionally built with high steeply sloped roofs to create an air space at the top of the house to collect the hot air in summer - allowing cooler air to fill the rooms below.
In addition we have external shutters on all of the windows and these are closed on the sunny side of the house. With an insect screen on the window you can the leave the window open as the shutters are not air tight so they allow a gently breeze to enter each room.
Also it is worth pointing out that the walls of my house are stone (60cm thick) and these act as a great heat sink.
It will probably hit 35C this afternoon but the house will remain cool.