We were the same with DD. We are living in the whitsundays atm and she would sleep in a nappy under the window with the fan full ball and still sweat!!! But the outside noise of crickets and frogs was bliss for getting her to sleep! miss that here in the city!.

But DS is a tummy sleeper so we have the monitor on in case.
I will have to get DH to check if it is auto or not. Is it on the control or the unit itself?