Planning for the weather is a good way to make your trip to Langtang relaxing and enjoyable, especially when you're splurging. The hottest months are usually April and March, with an average temperature of 27°C, while the coldest months are January and December, with an average of 23°C. The rainiest months in Langtang are August, July, September and June, with each month seeing an average of 261 mm of rainfall.