I am planning a trip to Northern India Himalaya region next year. When I visited Goa about 10 years ago, February and March seemed to be good months to go as it was not too hot. I had thought the same months for the Himalayas but would be interested to hear opinions about other times that might be good to visit.
Old post but comments somewhat related.
If you're planning to go to the Himalayas August - September is the best time. The roads are basically blocked by snow and avalanches 6 months of the year in winter and places like the Spiti Valley/ Leh and Ladakh are not practical to go to.
Friends and I went August - . September 2018. The loop was Delhi; Shimla; Rekong Peo; Spiti Valley; Keylong,Leh; Diskit; Pangong Lake; Leh; Srinigar; Kishtwar; Killar; Chamba; Dalhousie; Dharamsala and back to Delhi. Took 5 weeks but could have spent much more time exploring there.
I have a number of videos up on Youtube of that trip and a north of Vietnam loop we did last April. They aren't hyper-driven look at me and how dangerous this is videos like some self-promoters _ I put them up for me and my friends to show what the roads were like.,
Look up Scratchy Exma on Youtube (it will try to respell the search as Scratchy Eczma but ignore that).