If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Whitehouse: The hottest months are usually August and September with an average temp of 83°F, while the coldest months are February and January with an average of 79°F. The rainiest months in Whitehouse are May, October, September, and August, with each month seeing an average of 8 inches of rainfall.