Need newborn recommendations!!

So I have a two week old and a toddler!

Toddler is getting cabin fever, so I’d like to go outside and let him play in the yard/sprinkler/etc.

However it’s like 90° and humid as satans anus outside so I obviously don’t want to put baby in the boba wrap (we both get hot)

What is something I can sit a newborn down in/on safely outside to keep him safe but also not overheat?

Thanks!!