From my experience, Monterey a lot of times is cloudy and overcast, especially during the Fall and Winter. It usually clears up later on in the day, if at all. Living there for most of my life, I felt like you could have the weather of all four seasons in one day! It will be raining in the morning, overcast in the afternoon, sunny in the late afternoon, and frigid at night.
Because of Monterey's unique climate, a lot of agriculture is grown there or near there. Monterey's climate is perfect for growing grapes, as a result there are plenty of wineries around the area. Lettuce and many other fruits and vegetables are grown in nearby Salinas, as well as artichokes grown in Castroville, and garlic in Gilroy.
I might be a little biased since I'm from there, but I think Monterey's climate is perfect. It's not too cold and it's not too hot.
Areas with Mediterranean climate
Wine vineyards around Monterey
References:
1. Birdsall, Stephen S., Regional Landscapes of the United States and Canada (7th Edition)
2. http://en.wikipedia.org/wiki/File:Medclim.png (pic)
3. http://wine.appellationamerica.com/maps/Monterey.jpg (pic)