The short answer
What is the best month to visit the Andaman and Nicobar Islands? For dry weather and calm seas, the months from January to April are the safest choice. December is usually a good start to the season too. From May to September the south-west monsoon brings heavy rain, and October and November are still wet, though less so.
Temperatures change little through the year. Average temperatures on the islands range from about 23 to 31 °C, and sea breezes keep the heat bearable. That is why the question is really about rain, sea conditions and crowds.
Rainfall month by month
The figures below are long-term monthly averages for Port Blair from the India Meteorological Department, as published in the city's climate table on Wikipedia. Average rainy days are shown in brackets.
- January: 48.9 mm (2.2 days)
- February: 14.2 mm (0.9 days)
- March: 32.7 mm (1.8 days)
- April: 78.0 mm (4.2 days)
- May: 407.2 mm (15.9 days)
- June: 484.2 mm (18.7 days)
- July: 448.5 mm (19.3 days)
- August: 460.2 mm (19.1 days)
- September: 505.2 mm (20.0 days)
- October: 300.9 mm (14.9 days)
- November: 221.8 mm (10.4 days)
- December: 111.4 mm (4.9 days)
The total is about 3,113 mm a year, and the jump between April and May is the single most useful fact for planning: average rainfall rises roughly fivefold in one month.
The monsoon months
The Andaman monsoon season runs from May to September. The south-west monsoon is the wet one; the islands are usually dry under the north-east monsoon that follows. September is the wettest month in the Port Blair averages, with rain on about 20 days.
Worst time to visit Andaman
If you want beaches and boat trips, the months from June to September are the hardest. Rough seas can cancel or delay ferries, some water activities pause, and visibility for diving drops. That said, the forests are at their greenest and there are fewer visitors. Travellers with flexible plans and spare days sometimes enjoy the islands in the wet months, but it is not the season for a tight itinerary.
When to avoid Andaman and Nicobar Islands
Avoid the peak of the monsoon if your trip depends on fixed ferry connections or on diving. Also be cautious around the change of seasons in May, when the rain arrives quickly, and keep an eye on weather warnings at any time of year, because storms over the Bay of Bengal can disrupt sailings.
Season and the sea: ferries and diving
All ferries between Port Blair, Swaraj Dweep and Shaheed Dweep depend on the weather, so the dry months are also the most reliable months for getting around. For divers, PADI describes November to May as the best time to dive, with water temperatures of about 26 to 29 °C, and notes that the monsoon months bring rougher seas and lower visibility. Read more in the guide to scuba diving in the Andaman Islands.
The dry months are also the busiest. Around the end of the year and in holiday periods, flights and ferries fill quickly, so book early.
How many days in Andaman is enough
A first trip that covers Port Blair, Swaraj Dweep and Shaheed Dweep needs about a week. Count one day for arrival and Port Blair, two or three nights on Swaraj Dweep, one or two on Shaheed Dweep, and a last night back in Port Blair before your flight. Add two or three days for Baratang or the north, and more if you want to dive or learn to dive.
Once you know your dates, plan how to reach the Andaman Islands and book ferries early.