I work every day from 8 to 4, and my foster kitty, Tiny, who is about 7 months old, stays in the bathroom to prevent him getting into trouble or eating something poisonous (especially the roach bait I have in my cupboards). I have no air-conditioning.

I haven't worried before, but now that the temperatures are starting to get into the 90s, I'm beginning to be a bit anxious: Will Tiny be OK in the bathroom, with the blinds down to keep out the sun, all day? I give him ample water, of course; and the bathtub seems like it might be cool to lie in--I know he does because he leaves bits of litter and cat fur.

Considering that he's in the shade, indoors, will Tiny be OK in the bathroom? I know I would be because my work isn't air-conditioned either; but I'm a lot bigger than he is, and my sweat cools me down when I'm hot--Tiny's wearing a fur coat.

Advise?

Should be ok. Can you put a small fan in the room (or is there an exhaust fan) where the cat can't reach it?

http://www.thecatsite.com/Care/9/Keeping-Cats-Cool.html

did you see this already? there are some good tips on it.

No, I haven't. Good link.

Cats tend to gravitate toward the bathroom anyway in hot weather, since, yes, the tile floors and the tub are cooler to lie on. Providing lots of water is important... you can try putting ice cubes in it, though who knows if cats actually care.