Nepal has a temperate alpine climate.
The best time for trekking is during the autumn months - from late September to early December - as the days are warm and the skies are clear, offering spectacular views of the mountains.
The spring months of March and April are also popular, as the weather warms up and spectacular rhododendrons bloom.
The winter months of January and February can be extremely cold, especially at night, but will reward you with incredible views and quieter trekking trails.
The summer months are extremely hot and humid. From May the heat & humidity levels increase, until the monsoon rains arrive in June, when clouds obscure the mountains.