I was gifted those $1 disposable plastic rain poncho, typically for an emergency kit.
One odd July, had sudden showers on a 90F hot day. I would have welcomed the warm rain to cool me off, and clothes are polyester, but I wanted to experiment with the $1 disposable plastic rain poncho, in an non-emergency scenario.
it's disposable, because its vacuumed wrapped, once you unpack it, you will not be able to fold it neatly, similar to the Mylar convection foil emergency blanket.
plastic is noisy, then add the friction noise with the backpack, and then the sound of the water drops on plastic, NOISY.
but the main concern is hypothermia, and since I was still moving forward, I was greenhousing condensation body steam inside the poncho, which made it wet inside as much as the outside. Really defeating the purpose of water protection.
Poncho ventilation: the vents were in the back like a shorty cape mid-back, well my backpack kept those flaps closed. The front vent is the zipper, so I opened that up to air out, leaning forward to keep rain water out.
the hoodie on $1 disposable plastic rain poncho is junk, a little breeze and it blows back. gotta hold it down.
Glad I tested this "emergency" piece of junk in an non-emergency, so I know what to expect.
Now I have a dedicated rain jacket hoodie.
For the tent - internal condensation as well as the water drops on the outside. I use a plastic credit card size to comb the condensation dew off the inside walls. The next morning I comb the moisture off the exterior of the rainfly using a credit card, before I pack down my shelter. less water weight, less mold, less stink.