When you travel with your pet, keeping tabs on the weather can help you make the trip more safe and fun for everyone. The hottest months are usually January and December with an average temp of 79°F, while the coldest months are July and June with an average of 60°F. The rainiest months in Termas de Rio Hondo are January, February, December, and March, with each month seeing an average of 10 inches of rainfall.