Lonavala, the clichéd weekend getaway for Mumbai residents, consistently draws large crowds of visitors. Being surrounded by rich vegetation, monsoon season is when it shines.
A little hill town called Matheran, which translates to "forest on the forehead," is located in the Karjat area. While Pune is roughly 120 kilometres away, Mumbai is only about 80 km away.
Instead of driving or taking a bus from Mumbai, it would be fascinating to travel to Alibaug by ferry. Alibaug is home to the Kulaba Fort, which was constructed during the reign of the renowned fighter Shivaji.