Planning for the weather is a good way to make your trip to Posadas relaxing and enjoyable, especially when you're splurging. The hottest months are usually January and February with an average temp of 79°F, while the coldest months are July and June with an average of 62°F. The rainiest months in Posadas are October, May, November, and December, with each month seeing an average of 8 inches of rainfall.