It depends which state you would like to visit. for eg Meghalaya tourism is peak in monsoon. so that depends whether you love to travel during rains. otherwise, June or October is a good time.
The best time to visit is July, the onset of monsoon season. Cherapunji will be at its best then with active waterfalls. Laitmawsiang is a hidden treasure and is treat to eyes during monsoon.
Hlo Mannis If u want to visit in first half of year then mid March to mid of June and if planning for second half then in Nov and Dec as hornibal festival and other festivals in NE is during these months
No Matter What Time Of The Year You Plan To Travel, Northeast India Will Always Have You Hooked Upon It's Scenic Beauty Of Snow Clad Mountains, Breezing Lakes, Rolling Medows, And Definitely Incredible Wildlife.
October to Mid May Will Be The Best Months To Visit Unless You Want To Experience It's Breathtaking Rains During The Months Of June-Mid September! 😃
The best time to visit North East India is from October to mid May, which are the relatively dry months. But even in these months you do get occasional showers in the region. North East India mainly has a subtropical climate, influenced by the Himalayas to the north, the Meghalaya plateau to the south and the hills of Nagaland, Mizoram and Manipur to the east.