Interior spaces can be kept cool in hot weather without need for air conditioners, by using ventilation, thermal mass, shading, insulation and draught seals.
Vents or open windows let in cool outside air when available, or kept closed when outside air is warmer than inside air (unless airing the house). Vents at the top of a room or building can let out warm air (which rises up and accumulates near the ceiling), this air to replaced by cooler air from outside.
Captures coolness from available cool breezes, then slowly releases it to keep interiors cool despite hot outside conditions.
Prevents heat coming in through walls, ceilings, floors from hot outside air, walls, roofing.
Double and triple glazing on windows prevents heat gain through windows from warm outside air.
Keeps cool air in and warm air out.
Inside blinds or curtains, and outside awnings or shutters will keep unwanted sunlight from entering through windows. Nearby trees or bushes can keep the sunlight away from windows, and off walls, roofs and outside paving which might transmit heat to the building interior.
Ceiling fans provide a gentle breeze to keep people comfortable even when the interior becomes hot (eg over 27 degrees C).
North facing windows (in the Southern Hemisphere) are good for sunlight because simple eaves can block out high-angled midday Summer sun, while letting in low-angled Winter sun. East and West facing windows need more extensive protection from Summer sun, although they are good for obtaining heat from sunlight in Winter.