January and February are good months to visit Meghalaya, Assam and Nagaland, with average temperatures at lower elevations in the mid to high teens centigrade. Up in Gangtok in Sikkim it’s colder, with temperatures around 6°C or 7°C, but clear skies.
The only region that receives heavy snow is the higher parts of Arunachal Pradesh, in the Tawang area, making it hard to reach in January and February, although tailor made trips do still run now.
Late February, March and the first week of April are great times to visit Kaziranga National Park, as this is when controlled fires are lit to burn back the elephant grass, and visibility in these cleared areas is good.
Trekking around Sikkim and Darjeeling is best in March and April, September and October, outside of the rainy season, with clear skies and sun, and before the deep cold of winter.
May is heating up around the region, with Nagaland averaging a pleasant 20°C, Assam in the mid 20°Cs and Gangtok in Sikkim hovering between 13°C and 23°C.
The monsoon rains fall in June, July, August and early September in North East India. June is the wettest month throughout the region, and July tends to be the hottest, hitting the low 30°Cs at lower elevations in Assam and Meghalaya, and the mid 20°Cs in Nagaland and Sikkim. In Meghalaya, the town of Cherrapunjee, at the top of a high plateau overlooking Bangladesh, was the wettest place on earth until recently, when climate change skewed things. It gets a massive 1,145cm of rain a year. The average rainfall in the Brahmaputra valley is around 200cm.
During the rainy season, Kaziranga National Park is closed for four months from the end of May, reopening at the start of October.
The Hornbill Festival in Nagaland runs in the first week of December each year and tours to see it depart in late November.