There's nothing like an all-inclusive holiday in El Chalten to rejuvenate you, especially when you know what to expect from the elements. Here's some information to help you decide when to book: The hottest months are usually February and January, with an average temperature of 4°C, while the coldest months are August and July, with an average of -1°C. September and February are the driest months, while March and April are the rainiest months.