Taking into account the local weather in Cayos Los Grullos is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually June and September with an average temp of 80°F, while the coldest months are February and January with an average of 78°F. The rainiest months in Cayos Los Grullos are October, August, July, and November, with each month seeing an average of 12 inches of rainfall.