Weather will likely play an important role when you plan your trip to New Amsterdam, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and October with an average temp of 82°F, while the coldest months are January and February with an average of 79°F. The rainiest months in New Amsterdam are May, June, July, and December, with each month seeing an average of 17 inches of rainfall.