The Andaman and Nicobar Islands like other places in the region, including countries like Thailand and Singapore hardly sees any fluctuation in weather the year round. The best time, by far to visit the islands is from October to May which is when the annual tourism festival is held. Furthermore, this period coincides with the retreat of the monsoon which is when the water is as clean as it can get and it isn't too hot to spend a day on the beach. Temperatures generally range between 24 to 32 degrees Celsius immediately after the monsoons and may dip a degree or two below that in the winters. Irrespective of the weather, the Andaman and Nicobar Islands is always very humid!
Summers are hot and humid at the islands. This is not a very favorable time to visit since not many tourists make their way here in the summer months. Temperatures can go as high as 32 - 36 degrees Celsius given the proximity to the equator.
The Andaman and Nicobar Islands and particularly Port Blair receive a substantial bit of rainfall the year round particularly in the monsoon months immediately preceding May. The average annual rainfall is around 3000 mm and temperatures are a comfortable 24 degrees Celsius.
The winters in the Andaman and Nicobar islands don’t feel like winters at all with day temperatures remaining in the 24 – 30 degree Celsius mark and nights getting marginally pleasant.