Andaman weather month by month — and how monsoon affects ferries

Month by month, operationally

• December–January: best conditions, all ferries running, book 6–8 weeks ahead; peak pricing
• February–March: still excellent, thinner crowds, best diving visibility of the year
• April: hot and humid, sea still calm, prices soften noticeably
• May: pre-monsoon; sea gets choppy mid-month, first ferry cancellations appear
• June–August: full south-west monsoon; heavy showers, cheapest rates, real cancellation risk
• September: rain easing, sea still unreliable, good value if your plan is flexible
• October: transition; sea settles progressively, occasional cancellation
• November: sea calm again, green landscape, best value-to-conditions month of the year

How ferry operators differ when the sea is rough

The private catamarans and the government ferries behave very differently in a swell, and knowing which is which changes how you build a monsoon itinerary.

• Makruzz — enclosed high-speed catamaran, the most likely to still run in moderate swell, no outside deck, ~90 min Port Blair–Havelock
• Nautika — modern, fast, comfortable; similar sea tolerance to Makruzz, sells out earliest
• Green Ocean / ITT Majestic — good value, slightly more affected by sea state
• Government ferries — cheapest by far, slowest, most weather-sensitive, tickets released at the counter only a few days ahead
• In monsoon months always hold a private catamaran as primary and a government sailing as backup

The rules that protect you from a cancellation

• Never plan a Havelock departure on the same day as your flight home — always return to Port Blair the night before
• Keep at least one buffer night in Port Blair in June–September
• Book refundable or date-flexible hotel rates in monsoon months
• Cancelled sailings are usually refunded or rescheduled by the operator, but hotels are not
• Diving operators shut down on rough days regardless of ferry status

Should you travel in monsoon at all?

Yes, if you are flexible and price-sensitive: the islands are at their greenest, hotel rates drop up to 40%, and you get beaches to yourself. No, if you have fixed dates, a tight itinerary, or a Baratang and Diglipur plan that cannot slip.