Your Specialist will be able to tell you more about the region’s climate, including details of regional festivals, but here is a general guide.
India’s differences in latitude and altitude make for extreme regional variations. However, most places are at their best during the generally cooler period from November to February, after which the heat may be too much for many travellers to the central plains and south.
The monsoon hits different regions at different times as it spreads north and east from the Indian Ocean in late May, reaching the Himalayas around a month later. Building from high humidity and short rainstorms to absolute deluges, this is when the hill stations are at their best (and busiest), offering refuge from the plains below until October when the monsoon relents. Some northern cities can be surprisingly fresh by December, and of course the mountains are exceptionally cold in winter.
The main monsoon comes from the southwest, but the southeast coast (and southern Kerala) is largely affected by the short and surprisingly wet northeast monsoon, which brings rain from around October to early December.
Sri Lanka can be visited throughout the year, with the east coast glorious from May to October and the rest of the country best from November to April. The hill country can be chilly all year, especially in the evenings.
The Maldives can be visited throughout the year if one is prepared for the short but heavy, refreshing daily deluges of the twice-yearly monsoons.
Nepal’s mountain air is clear and fresh from October to December, dry and pleasant from February to April. January and February see cold nights, but good hotels and lodges will be heated and the chill keeps the trekking paths mostly free of large groups.
Some parts of Pakistan’s beautiful mountain regions may be inaccessible during winter, but are also gloriously scenic at this time. Spring and autumn offer a combination of more reliable access and pleasantly bright days.
Bhutan is best visited during its dry season, from October to May, although winter trips are possible - if cold - with beautifully clear air.