Weather will likely play an important role when you plan your trip to Kwajalein, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and August with an average temp of 83°F, while the coldest months are February and January with an average of 81°F. The rainiest months in Kwajalein are November, October, September, and August, with each month seeing an average of 13 inches of rainfall.