I Would suggest you go post monsoon season, after mid September. North East receives heavy rainfall and may make it difficult for you to travel unless you really love rain!
Places you should cover - Dawki, Living root bridges, Cherrapunji, Shillong.
There are pros and cons. In August, Meghalaya receives a good rainfall. So all the waterfalls are full of water with scenic views. Although, you may need to prepare for anytime rain. We recommend having a Raincoat handy if you prefer renting a bike from Guwahati or Shillong. Bike rentals in Guwahati are cheaper than those in Shillong. ( Disclaimer : We are a Bike Rental Company https://www.rentrip.in/rent-bike/Guwahati ) If you hire a car, rain should not bother you much, but you will miss some adventure as well. Meghalaya, is perfect for visit anytime in the year, however people prefer winters, as Kaziranga and some other destinations remain open during this time.
No August will be high rains season in Meghalaya. And In Meghalaya rains are not like the one in Delhi. It rains hard and longer. Also the terrain becomes too risky to travel. I would suggest you staright away replan your journey.
Prepare yourself to get drenched if you are planning in August. Meghalaya records highest rainfall during Monsoon. Main attractions are - Dawki, Cherapunji, Double Decker Root Bridge in Tyrna, Seven sister waterfall,
Meghalaya is known as The abode of clouds, and this title is best perceived if you visit the place during monsoon. This is the time when the grass looks a little more green, and the air is a little more fresh with sweet scent of wildflowers. And yes, when you roll down your car windows when you are on the way to Cherrapunji, clouds will actually play with your hair. So, if you don’t mind getting a bit drenched in the monsoon rain, August is the best time to visit this place. Let me know if I can help you with more details, will be glad to assist😊