Weather will be a little Hot in April to visit Pondicherry. Ideal time to visit is before March and after September/October. But again, if you are not averse to the heat, its good time to visit anytime.
Pondicherry is best visited during the months of October to March as the temperature usually ranges between 15 - 30 degree Celsius. Over the years, Pondicherry has truly been the gem of South India and an ideal vacation spot. Summers (April-June) are quite hot and the temperature touches 40 degree Celsius occasionally.