October to February. I went on December 31st weekend. It was slightly expensive that time. I think if you go in Feb, it will be nice. Anyway the place is beautiful. You can follow my writeup on it if you want to see the itinerary.
Best Time to Visit Pondicherry
October to March can be considered as an ideal time to visit. However, the town has different charms in different seasons. Here’s a monthly breakup of Pondicherry’s climatic conditions so that you can plan when to go: October to February: These months constitute the winter season in Pondicherry starting from October and February. It is during this time when the climate is comparatively cooler and also perfect for sightseeing, beach fun and water sports. Light woollens should be sufficient as during winters, the temperature usually doesn't go below 17 degree Celsius here. March to June: Pondicherry is at its hottest during its summer months starting from March to June, with the highest temperature usually not going beyond 41°C. However, the crowds are less, making it a good time to enjoy a peaceful vacation in this little town. Even water activities can be enjoyed as there is less number of people swarming at the beach. July to September: These months constitute the monsoon season in Pondicherry. The town receives heavy to light rainfall every year. Those who love to soak in the rain; this is the best time to let your hair down and experience the lush-green landscape of Pondicherry. Also, it is a good time to visit the city during the month of August as Sri Aurobindo’s birthday celebrations are held when the city is at its vibrant best.