The weather throughout northeast differs from region to region. The topography of northeast region is very dynamic.
In winter it snows in certain high altitude parts of Tawang region and Mayodiya region of Arunachal Pradesh, while it is reasonably cold in the plains of Assam and Tripura. The hilly platues of Meghalaya also witness very cold during winter, however, snowfall is not recorded yet. The hilly areas of Nagaland, Manipur and Mizoram also witness cold during winter.
During summer, on the other hand, it is quite hot in plains of Assam and Tripura. It is pleasant in Meghalaya, and the hilly areas of Nagaland, Manipur, and Mizoram. In Arunachal Pradesh, summer is not very prominent in the high altitude regions, but the low altitude regions witness a little hot weather.
To get exact idea about any place, please refer weather chart of that specific place.