When to go…

General best time to visit
October - March, when the weather is most likely to be warm, sunny and dry. September and April are considered shoulder months, especially in drier states such as Rajasthan but can be less busy and still a good time to visit.
Foothills of the Indian Himalaya
October until mid April with December / January cold at night.
Ladakh
Best visited between May - September, when the rest of the country experiences monsoon season.
Monsoon Season
Mid May - end August, Hot days and once the rains hit, sporadic heavy downpours. Worse in Western south (Kerala, Goa, Mumbai).
Wildlife Viewing
The best time for visiting the National Parks is February - April (April is getting hot). For photographers, April and May are considered the best months. Best to avoid parks from mid-June until early October (exceptions apply, such as Kaziranga in the North East, which is best from January to April).