Peru's distinct geographic regions have their own climates, so the best time to go depends very much on where you want to go and what you want to do. The coast is subtropical, with very little rainfall; the relatively mild winter lasts from June to September. The eastern rain forest region has an equatorial climate with hot temperatures and rain all year long. The Andean region has a very rainy summer season (December to April) and a dry winter that is often sunny during the day but really cold at night. In general, this May to October period tends to be the main tourist season in Peru, with those bookend months a particularly good time to visit.