Weather will likely play an important role when you plan your trip to St. Helena, but bear 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 temperature of 27°C, while the coldest months are February and January, with an average of 26°C. The rainiest months in St. Helena are October, August, November and July, with each month seeing an average of 209 mm of rainfall.