There is a fun winery in Half Moon Bay - La Nebbia

http://lanebbiawinery.com/

If you drive Skyline, there is also a good winery in the Santa Cruz Mountains called Thomas Fogarty

https://www.fogartywinery.com/

For more on the Santa Cruz wineries see

https://www.santacruz.org/food-drink/wineries-tasting-rooms/

Other areas close by and not as far as Napa include Alamade - great views of San Francisco Skyline

There are some awesome distilleries there too.

https://www.alamedaca.gov/RESIDENTS/Visiting-Alameda/Attractions-in-Alameda/Spirits-Alley

While Napa is your premier wine tasting area - there are plenty of individual wineries that are equally as respectable for tasting. Enjoy.

Just an FYI:

There was a huge fire in the Santa Cruz mountains recently and some wineries may have been impacted. The forest definitely was, so expect to see a lot of charred trees.

And please keep in mind that locals would appreciate it if you wouldn't do a lookie-loo drive through of the burn areas.

Yes, the fire may impact the OP's plans - the trip is 6 months away, so a lot of cleanup and regrowth will happen between now and then, but for any wineries that were damaged, depending on the amount of damage, that may or may not be enough time to reopen. It will be important to call ahead to make sure wineries are open. I think most wineries that are open require appointments for tasting right now anyway due to COVID. And of course, if the OP goes with a tour, then the tour operator will do that leg work.

We have driven in this area and except for Big Basin we are surprised that there is very little impact that we can see from the normal driving routes. Its fine to visit. You should not plan on going to Big Basin though (Visitor center, etc. burned down) until they let us know it has reopened.

We have been to all the beach parks from San Francisco to Monterey.

We have driven many of the hill roads.

So its fine now even to visit much of this area. During the fire, it was unhealthy due to the smoke.

We do feel sorry for those impacted and wish them well during the recovery phase.

You can stay out of the fire impacted areas and tour Summit Rd. and the Aptos/Corralitos areas.

For Summit Rd you can either take highway 1 from HMB to Highway 17 and exit at Summer Rd. or take Highway 1 to Bay/Porter, turn left to Old San Jose Rd to Summit Rd. The second option being more of a relaxing drive. Here are some wineries at the Summit

http://thesummitwineries.com/ Bargetto is near the bottom of Old San Jose Rd. in Soquel at N. Main Street. It’s very popular. http://bargetto.com/

Aptos/Corralitos has a mix of Vineyards and tasting rooms. Also many good restaurants in the area. Here’s an article on the Aptos/Corralitos wine trail https://www.google.com/amp/s/www.mercurynews.com/2012/09/17/traipsing-the-corralitos-wine-trail/amp/

A newly opened tasting room for Sante Arcangeli is in Aptos Village just off Soquel Dr. and Highway 1. http://www.santewinery.com/tasting-room/

There are also good restaurants in the immediate areas. Cafe Sparrow http://cafesparrow.com/

Mentone https://www.mentonerestaurant.com/

and Persephone https://www.persephonerestaurant.com/

This post has been removed at the author's request.

thank you for all of the replies. We are on the east coast but watched footage of the fires intently. Absolutely terrible.

I'm leaning toward the Ritz Half Moon due to its beauty and now that I know we can get some great wines (and support the local economy so heavily impacted by the fires), that's probably what we will do.

I still feel a little conflicted about being so close to Napa/Sonoma, but not close enough for a day trip.

thanks all

The Ritz Carlton at Half Moon Bay is superb. Enjoy your trip.

California has a lot of wine regions - Napa and Sonoma are just the most well-known, so that's what people tend to think of first. There's great wine all over California though.