The weather on Isla Mujeres is usually what you hope for... perfect! The average temperature is around 80 degrees. The humidity can get pretty high during the summer months, so when weather.com reports the temperature as 85° but "feels like 100°" believe it! During the winter months, occasionally there is a "Norte" which brings a cold front from the north so be sure to bring a sweater or light jacket for the evenings. The winter months are the driest with only an occasional afternoon shower. Even when it's raining in Cancun, Isla is often sunny. The summer months are wetter but the storms pass by quickly unless there is a tropical depression.
Averages for Isla Mujeres
The official hurricane season is from June through November but September and October are the months when tropical storms and hurricanes are most likely. It is always a good idea to purchase travel insurance, even more so during hurricane season. For the most comprehensive information regarding approaching storms visit Dr. Jeff Master's Wunderblog.