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 temperature of 26°C, while the coldest months are July and June, with an average of 17°C. The rainiest months in Posadas are October, May, November and December, with each month seeing an average of 205 mm of rainfall.