Because of the increased humidity during the wet season, air con as suggested by scubascuba3 is probably your best solution, as cooling the air also reduces the humidity.
I put my A/C on for a short period to cool the room, then turn it off and use a fan to circulate the air.
In the hot season, I might wake up in the night and repeat if it gets too hot.
I have found that putting towels along the bottom of my sliding doors and the bedroom door makes a hell of a difference in keeping the room cooler for longer. it stops the cold air seeping out.