Weather will likely play an important role when you plan your trip to Guwahati, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually April and May with an average temp of 81°F, while the coldest months are January and December with an average of 68°F. The rainiest months in Guwahati are July, August, June, and September, with each month seeing an average of 24 inches of rainfall.