When to go and weather in Nepal

Nepal is not one trekking season. It is a stack of climates: Terai heat, Kathmandu Valley weather, mid-hill rain, high-pass snow, rain-shadow exceptions and altitude that changes the night faster than the map changes the day. The question is not “Is Nepal good in October?” It often is. The better question is: which trail, which altitude, which side of the monsoon, and how much crowd pressure are you willing to accept?