Best season for trekking in Nepal is Spring (March, April, May) and autumn (Sept, Oct, Nov). During this time, the weather is pleasant and sunny. The sky is clear mostly which means that you can truly enjoy the remarkable Nepalese landscape and Himalayan vista.
During the monsoon (June, July, Aug) although there will be no problem for trekking. During the monsoon, the view will not be clear. If you are a keen botanist, the monsoon is a blessing as the higher valleys, mountains, and meadows blossom with flowers and abundant vegetation. There are a lot of things that you can do here in Moonsoon time. There is tour options. Nepal tour can be done any time of the year. December, January, and February is the cold month of Nepal. Even it is winter you can still do the trek. there are short trek options such as Ghorepani Ponnhill and Mardi Himal Trek in Annapurna. In Langtang, you can do Langtang valley trekking.
|1||Mid-September, October, and November are Autumn Season:||This is the best time to do trekking because in this time the field is full with crops, the forest is very green and there is no chance of rain.|
|2||March, May||During this time the forest becomes very colorful because of rhododendron and magnolia flowers as well as very less chance of rain.|
|3||December, January, and February||the sky is clear but the weather is cold and there is a risk of hailstorm and snowfall. This is not good time to trek.|
|4||May, June||this is Monsoon season and the least popular time to do trekking in Nepal. The risk of leeches, landslides, floods and so on.|