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 temperature of 13°C, while the coldest months are August and July, with an average of 7°C. The rainiest months in Lago Ranco are June, August, July and May, with each month seeing an average of 400 mm of rainfall.