A quality holster made of horsehide or cowhide treated with a water sealant from the manufacturer will not suck up moisture...and will last for years of hard use.
I dont know what you do for a living or how bad you sweat, but I never had good luck with leather, especially in the summertime. SE PA gets steamy hot, with temps hanging around the upper 90's and high humidly. If you work outside, any exertion will usually have you soaked pretty quick. A lot of days I'm soaking wet from sweat by 9:30, and stay that way the rest of the day.
Over the years, I tried leather holsters from a lot of the major makers, smooth out or rough out, with little difference in the results. Once summer arrived, they were constantly wet. I usually tried to rotate through a couple of holsters. This was only marginally effective as they still dont dry out over night once they soak through.
After switching to kydex, there is no way I'd go back to leather for a daily, hard use holster. Most of the better leather holsters cost almost twice that of kydex, and wont last long if you use them hard daily. If you only wear your pistol occasionally, and/or move from a climate controlled car to the climate controlled office, your results will probably be a little different, but even then, the kydex will still last forever, never loose shape, and can easily be adjusted for tension at any given time.
This was the last new leather holster I used with my Commander, a Royal Guard, after about a months use (and about 8 years of storage in a box) in the middle of the summer. The duct tape was there to try and slow the sweat, which didnt work to well.
This is the Blade Tech kydex IWB (on the right) that replaced it and was used daily, year round, for about 10 years.(the holster on the left is a new one I had recently bought for a Government model for comparison) In all that time, I replaced a couple of straps and a small piece of the sweat shield broke off. The holster still worked then like it did the day it was new. Once I went to kydex, the only part of the gun to get wet was the grip panel, and some of the safety area on my body side.