Planning for the weather is a good way to make your trip to Rioja relaxing and enjoyable, especially when you're splurging. The hottest months are usually September and October with an average temp of 69°F, while the coldest months are July and June with an average of 68°F. The rainiest months in Rioja are March, April, February, and January, with each month seeing an average of 13 inches of rainfall.