In the month June, July and August Nepal put up with monsoon season. Trekking in Nepal in these months is not much recommended since the heavy rainfall makes the trails muddy and slippery. Also, you may have to go through flight delays or cancellation which can crop up quite often during the monsoon. In addition, because of cloudy environment, the blue patches in the sky as well as the views of sunrise and sunsets, snow capped peaks, etc will be seen very rarely.
During monsoon, mosquitoes and leeches are also very common. You will need to carry mosquito repellent cream wherever you go and we highly recommend you to carry long boots if you want trek in this season.
Apart from its disadvantages, monsoon can be an idyllic time for a number of trekkers who love to merge trekking experience with thrilling rafting experience. Monsoon is the perfect time for white water rafting. The thrill you can enjoy from different levels of rapids of white water in monsoon cannot be compared with any other season. The lush environment in addition appeals botanists to do their research on plants. Monsoon is also a best time for you, if you want to get pleasure from yoga and meditation.