Weather will likely play an important role when you plan your trip to Picayune, 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 27°C, while the coldest months are January and December, with an average of 13°C. The rainiest months in Picayune are August, July, June and May, with each month seeing an average of 204 mm of rainfall.