If you’re looking forward to lots of outings with your partner, check out these details about year-round temperatures in Lajeado: The hottest months are usually January and February with an average temp of 74°F, while the coldest months are July and June with an average of 58°F. The rainiest months in Lajeado are October, September, July, and January, with each month seeing an average of 7 inches of rainfall.