WiFi hygrometer

SuperBabyMethod:
Is there any particular board required to use 2 shields at once?

It is possible to use multiple sheilds with any Arduino, provided they either aren't using the same I/O pins or all of them use any shared I/O pins in a way that doesn't interfere with the other shields.

Shieldlist.org is a good resource checking what pins are used by a specific shields.