They are made to be cooked outside in the elements, but water"proof", I don't think that it is. My YS640 had been used in some heavy rain (think gully washer) and heavy snow (think blizzard) and I didn't have any problems with the controller. And for the record, those conditions were NOT predicted when I started the cook. Farkin' weather men.
Yoder Smokers YS1500, Kamado Joe BigJoe & Joe Jr., Weber: 18.5" OT(L), SJG(AU) & (DI) - Past Cookers: Yoder Smokers YS640 Comp Cart, Kamado Joe Classic, OKJoe's Longhorn, UDS, Weber: Performer(AA), Genesis Gold C(DH), 22.5" OTG(DI), 22.5" OT(L)
IMBAS Certified MOINK Baller