Drinking and dining in the Napa Valley is a treat at any time of year, but there are still factors to consider when planning a trip.
Heat
In the summer months, the weather in the Napa Valley is very warm. It is not uncommon for it to be over 100 degrees Fahrenheit (37.7 degrees Celsius) on a summer day. July is most commonly the hottest month of the year followed by August, September. At all times of the year, the heat dissipates in the evenings. You will want to have a light sweater or wrap with you, even if it was sweltering during the day.
Rain
December and January are the rainiest months of the year. Early February can also be rainy. It rains very rarely between mid-May and early November. During the time of year when there is no rain, the brush on the hillsides is brown. If you are concerned with encountering green grass on the hillsides, consider traveling in late February or March.
Seasonal and Regular Closures
Many restaurants and wineries are closed the last week of December and the first two weeks of January. If a winery or restaurant closes one day each week, that day is most likely going to be Tuesday.
Best Days to Visit Wineries
The weekends are the most popular time to visit Napa wineries and this is when the tasting rooms are busiest. Visiting with the crowd does have a possible benefit; some wineries will open additional bottles for tasting or do barrel tastings on the weekends. Thursdays and Fridays are the best days for tasting as the wineries are ramping up for the busy weekend but the crowds have not yet arrived.
Harvest
The grapes in Napa are harvested in parts of September and October. If you want to do a tour with a winemaker, do not come during the harvest. Be aware as well that many hotels in the region raise prices at this time of year.
Transportation Considerations
The roads into Napa Valley from San Francisco are small and crowd easily. If you can avoid it, do not drive from San Francisco to Napa on Fridays between about 2:00 p.m. and 7:00 p.m. If you must drive during these times, plan at least an extra 40 to 80 minutes to reach your destination. Similarly, returning to San Francisco on Sunday afternoon can be very unpleasant traffic-wise. Holiday or event weekends also clog the roads and can make driving difficult.