I don't know if it will be of any use in hot humid weather, but
since I have been using shikakai/amla, my hair has been remarkable.
I have been out on the rain numerous times and my hair never reverted
! I do however spray on a leave-in and then lightly and I stress lightly add some serum and then proceed to aa air dried ponytail roller set
(5 pony tails). Once dry, I used to flat iron the roots. I haven't had to do that lately either
. I have been transitioning, so there is a lot that could have reverted in the rain
.
Before my current regimen, if I went out into the rain, you could pretty much call it a day, so to speak. Now I only flat iron the roots if I want it to look absolutely bone straight.
HTH