Planning for the weather is a good way to make your trip to Manaus relaxing and enjoyable, especially when you’re splurging. The hottest months are usually September and October with an average temp of 84°F, while the coldest months are June and April with an average of 79°F. The rainiest months in Manaus are April, March, February, and May, with each month seeing an average of 15 inches of rainfall.