South Asia has no single best season. The region spans the Himalayas, desert, rainforest and tropical islands, and the monsoon arrives at different times in different places. Still, a few patterns hold for most visitors: October to March is the most comfortable period for the plains, while the mountains have narrower windows in spring and autumn.
The big picture
Southwest monsoon (June–September). Heavy rain falls across much of India, Nepal, Bangladesh and western Sri Lanka. Landscapes are green and prices are lower, but flooding and landslides can disrupt roads and flights, and mountain views are often hidden by cloud.
Cool, dry season (October–March). This is the most popular period for northern and central India, Nepal and Bhutan. Skies are clear and temperatures are pleasant, though nights can be cold at altitude and in places like Rajasthan in December and January.
Hot season (April–June). The plains of India and Nepal become very hot, with daytime temperatures often above 40°C in Delhi, Agra and Rajasthan. Many travelers head to hill stations such as Shimla, Darjeeling or Munnar instead.
Country by country
India. For the Delhi–Agra–Jaipur circuit and Rajasthan, go between October and March. Kerala and Goa are at their best from December to February, with calm seas and low humidity. Ladakh is a special case: the roads open around June and the region is best visited from June to September, when other parts of India are in monsoon. If you want to see tigers in parks such as Ranthambore or Bandhavgarh, the dry months from March to May give the best chances because animals visit waterholes, though it is very hot.
Nepal. The two main trekking seasons are October to November, when skies are clearest after the monsoon, and March to May, when rhododendrons bloom at lower altitudes. December and January are cold but still good for lower treks. Avoid the main high-altitude passes during the monsoon, though areas north of the Himalaya, such as Upper Mustang and Dolpo, are in the rain shadow and can be visited in summer.
Bhutan. The best months are March to May and September to November. Spring has flowers and festivals, and autumn has the clearest views. Summer brings rain, and winter is cold at altitude but sunny and quiet.
Sri Lanka. Two monsoons affect opposite sides of the island. The west and south coasts, including Colombo, Galle and Mirissa, are best from December to March. The east coast, including Trincomalee and Arugam Bay, is best from about April or May to September. The hill country around Kandy and Ella is pleasant for most of the year, but February to April is usually driest.
Bangladesh. November to February is cool and dry, which makes it the best time for the Sundarbans mangroves, Sylhet’s tea gardens and Dhaka’s old town.
Festivals worth timing a trip around
- Holi (February–March, date varies): The festival of colors marks the arrival of spring. It is most lively in northern India, especially in Mathura and Vrindavan. Wear old clothes and protect cameras and phones.
- Diwali (October–November, date varies): The festival of lights is celebrated across India with oil lamps, fireworks and sweets. Expect crowded trains and higher hotel prices.
- Bhutan’s tshechu festivals: These masked dance festivals take place across the year. The Paro festival is usually held in spring, and the Thimphu festival in September or October. Book a licensed tour operator early, since visits to Bhutan are arranged through a licensed operator and fees are fixed.
- Vesak (May): Sri Lanka celebrates the birth, enlightenment and death of the Buddha with lanterns and processions.
Festival dates follow lunar calendars and change each year, so confirm them before you book.
Practical tips
- Book treks and flights early. Everest Base Camp, Annapurna and Bhutan’s popular treks fill up in October and November. Booking guides, lodges and flights to Lukla several months ahead is wise.
- Allow spare days in the mountains. Flights to and from Lukla are often delayed or canceled because of weather. Keep a buffer before any international departure.
- Plan for temperature swings. Mountain days can be warm in the sun and below freezing after dark. Layers and a warm hat are essential.
- Look after your stomach. Drink filtered or bottled water, eat freshly cooked food and carry rehydration salts. Introduce spicy dishes gradually.
- Check train and hotel availability. Indian trains can sell out weeks ahead during festivals and in December and January.
The short version
For a first trip, aim for November to February in India and the south, and October–November or March–April for the Himalaya. If your dates are fixed outside these windows, choose the regions that suit them: Ladakh in summer, Sri Lanka’s east coast from May to September, or the hill stations in the hot season.