I have visited El Arenal many times over the last 8 years and in my opinion the best time to go for the weather and sunshine is the middle of May or torwards the end of September. It is usually around the 80 degree mark then but in the summer months it is very humid and unbearable. If you don't have air-condition in your hotel and when you go out at night, the humidity is still very high.

But when you think about it you are in Espania...............Lolllllllll