Weather will likely play an important role when you plan your trip to Samut Songkhram, 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 85°F, while the coldest months are December and January with an average of 80°F. The rainiest months in Samut Songkhram are September, October, May, and July, with each month seeing an average of 8 inches of rainfall.