Weather will likely play an important role when you plan your trip to Cozumel, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July, with an average temperature of 28°C, while the coldest months are January and February, with an average of 25°C. The rainiest months in Cozumel are June, September, October and August, with each month seeing an average of 213 mm of rainfall.