I visited lachung in the month of March.But I recommend you to go in April.because we can’t visit yumthang because of heavy snow falling.The roads were blocked.So April is the best time.lachung is a very very great place if you are a nature lover.the valley is no doubt Amezing.In night you can enjoy the sound of the river in the valley from your hotel .Many homestay and hotels are providing accommodation.you can go to cataw and enjoy swizerland in like feeling in India. After all I say go and enjoy snow falling there with your family and friends.