Thailand or Indonesia for travel in September?

Hi all!

As the title says, I’m planning a trip in September and need some advice. I’ve narrowed it down to Indonesia or Thailand, mostly due to ticket prices.

The thing I’m concerned about is it being the rainy season in Thailand, as I will be outdoors most of the day. As for Indonesia, the vastness of it and the fact that it isn’t as popular of a destination as Thailand makes me nervous as this will be my first time in Asia solo.

Let me know what you all think, and if anyone has experience backpacking solo in both countries I’d love to hear them!

TIA

Thailand or Indonesia for travel in September?