I'd recommend around 65-75, although they can probably tolerate a little higher/lower. The humidity I wouldn't worry too much about. As long as the coco fiber is a little moist and they have fresh water to soak, he/she should be pretty happy. If you want to read a little more on them there is a guide on this site:
http://www.frogforum.net/content.php...ytes-Pelobates