Avoiding the crowds in Napa and Sonoma

If you don't like pushing-and-shoving, stop-and-go traffic, loud people, and lousy service it's important to know when and where to visit.   Wine tasting can be a not-so-nice experience when you have to leave a tasting room without getting served because the crowd is three-deep at the bar and then find you have to wait 15 minutes to make a left turn onto the road.    I've just described Highway 29 in Napa Valley on any weekend during six months of the year.

Welcome to Napa Valley!

Geography
Napa is much more crowded because it's famous and because the winery tasting rooms are densely packed along the main road.   Sonoma is more spread out and generally has fewer visitors.
Highway 29 in Napa Valley is much more crowded than the Silverado Trail that parallels it to the east.  29 is lined with tasting rooms.
Places to the south tend to be more crowded as they are a closer drive from San Francisco and the rest of the Bay Area.   In Napa go north of Calistoga, in Sonoma north of Healdsburg, to find fewer people.

Time of year
The busy season is roughly May through October with a couple exceptions.   June is actually relatively light in traffic.  Most holiday weekends, whatever time of year, are more crowded.  This is especially true of Thanksgiving weekend as people like to take their visiting relatives out wine tasting Friday and Saturday.   Labor Day weekend?  Stay the heck outta Napa!
Autumn is quite busy, especially on weekends, as there are many people that like to come out during the harvest.  The harvest is roughly Sept through Oct.

Time of week
Obviously, the weekends are much busier and mid-week the lightest traffic.   This is especially true in the off-season as there are fewer people on vacation. In high-season you'll find many popular Napa wineries pretty crowded every day.  In the off-season almost every Saturday will still bring out the crowds.

Time of day
The peak times are in the afternoons beginning about 1:30 pm.   There is a bit of a lull as people have lunch between about noon and 1:30.   Friday and Saturday are especially busy in the afternoons.   The Sunday traffic tends to die off mid-afternoon as the Bay Area people head home.

Location
Certain places will draw more people, such as Mondavi and Beringer.  So, for instance, stopping at Mondavi on a Saturday afternoon in August is a good idea only if you like crowds and noise.   Going to Mondavi on a Wednesday in winter is a whole different experience.
Towards the end of the day people are working their way south back towards San Francisco meaning the wineries in southern Napa and Sonoma will be busier at 5 pm.

Welcome to "downtown" Geyserville in Sonoma County
Image from winecountrygetaways.com

Avoiding the crowds
Plan your trip in the off-season.
Plan your wine tasting during the week rather than weekends.
If you can't make either of these work then go to Sonoma County rather than Napa.
During peak times go for the smaller, less known wineries in northern Napa or Sonoma county.