Post bathing I guess it's ok, don't know for sure, because usually the only time I bathe (my horse, not me!) is before a show, so it's banding/braiding & his jammies on. I know saddling up a wet horse from being out in the rain is stinky!
/shrug. It's really hot and humid here most of the time, so I just think about how uncomfortable it would be to be wet under my clothes in the humid heat... I can't imagine it would be comfortable for a horse to be wet under his saddle.
I do it all the time in the summer when it's reallllyyyy hot, just try if you can to avoid the saddle area if your just hosing your horse off because it's hot, just avoid the saddle area just so it's more comfortable for the horse. (:
I have an amazing horse towel blanket ! My mom had a lady make if for me its I love it ! Its not hard to make and they dry very fast ! And I personally hate saddling a wet horse, I find my western saddle moves around to much !
I say nay, only because I only bathe my horse before a show, and letting her dry off before tacking up keeps her coat uniform and smooth. But I wouldn't say it does anything more than a bit of aesthetic harm.