The weather is warm all year round (yearly average temperature 27°C/82°F).
The driest months are February, March, September, and October.
The rainiest months are May, July, November, and December. Weather patterns change rapidly and are rather hard to predict.
Please note that, even when it rains, the water is always very warm and, as soon as, it stops everyone has always been enjoying kayaking or swimming the lagoon.
Also overcast day can be perfect for excursions, like jungle hikes, or having the kids play on the beach. Panama is outside of the hurricane belt.