Visiting local bars in Denis Island is better when you know what the weather holds. These rainfall averages and temperatures can help you determine the best time for bar hopping. The hottest months are usually April and May with an average temp of 83°F, while the coldest months are July and August with an average of 80°F. The rainiest months in Denis Island are January, December, May, and November, with each month seeing an average of 10 inches of rainfall.