Planning for the weather is an important factor for making your trip to Lago Ranco a success, especially when you're splurging. The hottest months are usually January and February with an average temp of 56°F, while the coldest months are August and July with an average of 44°F. The rainiest months in Lago Ranco are June, August, July, and May, with each month seeing an average of 16 inches of rainfall.