The best time to visit Sawantwadi is October to February, after the monsoon has cleared and the air is cool and clear. The surrounding countryside is lush and green in these months and daytime temperatures are comfortable (20–28°C). The Konkan coast nearby is at its best in this period.
March to May gets hot and humid before the monsoon arrives. The monsoon itself (June to September) brings very heavy rainfall to this part of the Konkan — Sawantwadi is in one of India's highest-rainfall zones — but if you don't mind the rain, the waterfalls and forests at Amboli Ghat are spectacular in the wet season. Travel can be disrupted by flooded roads, so check conditions before heading into the ghats.