India has no single best time — it depends where you are going
India’s climate varies so dramatically by region that “best time to visit India” is almost a meaningless question without specifying where. Here is the regional breakdown.
North India (Delhi, Rajasthan, Agra)
October to March: excellent. Cool to warm days, minimal rain, comfortable for sightseeing. December and January can be cold (Delhi gets surprisingly cold — down to 5°C at night). April and May: hot and getting uncomfortable. June to September: monsoon, extremely hot before the rains arrive in late June. I would strongly avoid north India in May — 45°C in Rajasthan is genuinely dangerous for touring.
South India (Kerala, Tamil Nadu, Karnataka)
November to March: best for most of South India. Kerala has two monsoon seasons — June to August (southwest monsoon) and October to November (northeast monsoon). The northeast monsoon hits the east coast (Chennai, Mahabalipuram) hardest. December to February is the reliable dry window for the whole south.
Himalayas (Himachal Pradesh, Uttarakhand, Ladakh)
June to September: trekking season, roads open, dramatic landscapes at their most accessible. Ladakh specifically is best July to September. Winter at altitude is extremely cold and many roads close.
Goa
November to February: peak season, perfect weather. March to May: still dry but increasingly hot. June to September: monsoon, most beach operations close.
My recommendation
November is the single best month for the most flexibility — north India is comfortable, south India is in its sweet spot, Goa is entering peak season. Book flights early for November — it is increasingly popular. Check Kiwi.com for the best fares.