Hi Amrutanshu,
August is the middle of the monsoon season in Goa, so you can expect some rain. However, the rain is usually short and sharp, and there are often sunny breaks in between. If you don't mind a little rain, then August can be a good time to visit Goa, as there are fewer tourists and you can get some good deals on accommodation. It is very much safe and definitely worth it.
Here are some places you can visit in Goa during the monsoon season:
Dudhsagar Falls: This is one of the most popular tourist destinations in Goa during the monsoon season. The falls are located in the Bhagwan Mahavir Wildlife Sanctuary, and they are a beautiful sight to see when they are cascading down the mountainside.
Mollem National Park: This is a great place to go for a hike or a nature walk in the monsoon season. The park is home to a variety of wildlife, including elephants, tigers, and leopards.
Chapora Fort: This is a 17th-century fort that is located on a hilltop overlooking the Chapora River. The fort is a great place to visit in the monsoon season, as it is a lot less crowded than it is during the summer months.
Anjuna Flea Market: This is a popular market that is held every Wednesday in Anjuna. The market is a great place to find souvenirs, clothes, and handicrafts.
These are just a few of the many places you can visit in Goa during the monsoon season. If you are looking for a more off-the-beaten-path experience, you can also visit some of the smaller villages in Goa. These villages are often very charming and they offer a glimpse into the local culture.