I'd only water if the vines are showing stress before version. After that I stress mine, research here in Washington shows that can improve wine quality. Watch the tendrils, if the get shorter than the tip of the shoot, it is stressed. Alternatively, if the leaf to pitole angle is less than 90 degrees, it is likely water stress. There are lots of soil moisture methods out there but I find the tendril and pitole indicators easy. Of course young, non-bearing vines will need more water particularly in the spring. Don't irrigate in the fall except a shot after harvest if it has been really dre, so the vines will harden off for the winter.
With 35 inches of rain, and assuming you get 2-3 of that before version, I'd be surprised if you ever need to irrigate. I'm in the desert, 8.5 inches, so we watch it pretty close.