HI Ansuka, The area receives minimum fluctuations in the temperature and is always pleasant. The best time to visit Andaman Nicobar Island is considered from November to May. Monsoons are however recommended to be avoided for Andaman Nicobar tour because of the high tidal waves, incessant rains and strong winds. Hope this helps!
November, December, January and February are the best months to visit Andaman and Nicobar. This is also the peak tourist season so make sure to book everything in advance (flights, hotels, ferries, slot for water sports).