If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Grogol: The hottest months are usually October and September with an average temp of 78°F, while the coldest months are August and September with an average of 77°F. The rainiest months in Grogol are February, March, January, and November, with each month seeing an average of 18 inches of rainfall.