Ah, the wind - turns out we lucked out on that. During the ride we encountered some headwinds but not too bad.
My friend (who accompanied me on the 40 mi ride) and I were told afterwards that just a day or two before the winds were up to 30 mph, and when Lee and I drove home the next day the winds were plenty strong from early morning onwards.

Geological factoid: the Sutter Buttes are considered the smallest mountain range in the world. They are pretty odd-looking, as you approach the area they appear as a clump of hills jutting out of otherwise completely flat land. http://www.syix.com/yubacity/sutterbuttes.html