Sonoma County alone saw more than 30 vehicle crashes between 7 a.m. and 5 p.m. today, California Highway Patrol Officer Jon Sloat said.
Only two of these collisions sent passengers to the hospital with moderate injuries while the others were non-injury crashes, he said.
But nearly all of the crashes were attributed to unsafe speeds for wet road conditions, according to Sloat.
The CHP is reminding drivers slow down, ensure that windshield wipers are in good condition, and keep headlights turned on.
The National Weather Service is expecting light showers to continue this evening, meteorologist Chris Stumpf said.
The weather is expected to clear up Tuesday before a new and stronger storm system from the Gulf of Alaska passes through the region on Wednesday.
"It looks like we might get a decent soaking on Wednesday," Stumpf said.
The heaviest rain is expected to move through the area early Wednesday and light showers and possible thunderstorms are expected Wednesday afternoon.