Hi again bikesd. I got misted on this morning as well! I had an interesting ride (for the purposes of your question) this morning. Usually I don't wear gloves. But this morning I ran 2mi, and was totally sweaty, so I wore biking gloves, because otherwise my sweaty hands are quite slippery on my bar tape (drop bars, regular bar tape). But on the way to work I stopped at a place to get blood drawn for my annual checkup, when I left there I was no longer sweaty, so I didn't put my gloves back on. But then because of the mist, all of my skin got wet, including my hands on the bar tape.

Short story: wear biking gloves to control slippery grips.

In the rain, the grips will still get wet, but the gloves will probably absorb and not slip around so much.

Also I've heard that Schwalbe Marathon Supremes are very good rain tires (just one of the characteristics that make them the gold standard for commuter tires), but they are pricey. Others probably have other recommendations.

All in all though, this is San Diego, you shouldn't have to worry about too much rain. Although 1.5 inches in one weekend in July? Unheard of! (And I've heard this is going to be a crazy wet El Nino winter...)

One last tip: I bought an Ikea rain poncho for like 6 bucks, and carry it around with me. It packs into its pocket, which is pretty convenient. Haven't gotten a chance to try it out yet though...