I am looking at getting one, but have a question. I am here in hot, humid sunny Florida. Is the mesh really heavy or is it pretty breathable? I'm just concerned that during our hotter months it would be too hot to even wear for 30 min or so.

I'm in the delta, where it's very hot and humid and it really is too heavy to wear during the summertime down here. I love, love, love it when it starts to cool off but it stays hanging in the trailer for about half the year. Mine came with a BOT saddle pad liner that I really like and will stick that on in the summer if someone has a sore back or I just want to loosen them up :)

It is thick. Its 2 layers the good stuff then a mesh on top. It's not just breathable mesh saddly. Wish it was! 

I'm in Alberta canada so I use mine year round but I am diffently more careful in the summer and I dont do it up in the summer I just throw it on. My horse works much better if she can wear it 15-30 min before I saddle her. 

I'm in central IL and couldn't use mine at all in the summer when I had one 

I like my BOT but it gets too hot in the summer I only use it at night. 
I think I'll go a different route when I'm ready to by another sheet, something I can use year round.