Raybo is right. Cold & wet.
North - Napa - is wetter than south - San Juan Bautista.
Coastal - Santa Cruz is wetter than Inland - Rio Vista.
You don't even want to consider up north, Ukiah. (7.24 precip)
The interior valleys of the Coast Range are much drier, King City. (1.80 precip)
Depends on when the rainy season starts and how intense it is.
In an average year you may alternate between rainy and sunny days.
But the earth is refreshed and the hillsides a lush green.
A wet season may have torrential rains and mudslides.
A dry season may have significant closures due to fire risk and burn areas.
A loop out of Monterey might work - - might.
South along the coast - then to Mission San Antonio -
Then up the Salinas Valley and over to Pinnacles.
To San Juan Bautista and back to Monterey.
Limited services, some closed, but doable.