Ghats in Maharashtra are spectacular during monsoon, which starts in mid June in general. But if you ask me I suggest you visit ghats in starting of September. You can avoid heavy downpour and still get drizzles in ghats. Surrounding is lush green and clouds hover over head. It's awesome๐
You should visit Mahabaleshwar in Nov-Jan. Best time as it will be strawberry season and weather is just perfect. Stay in Panchghani rather than Mahabaleshwar itself.
You can visit Bhandardara, a beautiful place to spend weekend in Maharashtra. In Bhandardara you can visit Umbrella Fall, Wisdom Dam, Randha Falls, Kalsubai Peak and many more places. If you are planning to come The Yash Resort is the best place to stay. There they have swiming pool and a awesome pool side cafe named YOLO Cafe.