Surviving Heatwave With 7mo?

So we're expecting a heatwave to start tomorrow and last to mid week overnights averaging 20°C days 30°C+ with humidity!!! We don't have a/c, only exhaust window fans and a good crossbreaze when there is wind... I'm so worried about my son being too warm at night but he's too big to sleep anywhere but his crib and the nursery has the least cross breaze. He's my first and only child so I don't know what to expect. Anyone live in hot climates who can reasure me that he'll be fine in a 20-26°C room overnight? Or should I put a fan on him in his room? Or? Any suggestions?