Did you ever wonder why Napa Valley grows some of the best wine-making grapes in the world? It's because of the perfect grape-growing weather. The hot summer days keep the fruit growing to ripeness, but the cool nights help them to retain their freshness and ideal acidity levels, something that's important for wine making (but not for grape juice).
The average yearly temperature for Napa is 70° F, if you can believe it, F. Only 2% of the world has such a perfect, Mediterranean climate! Napa is also famous for its 14 microclimates, each of the valley's wine appellations have a slightly different climate, making them ideal for different grape varietals.
You can practically watch the vines growing in the hot, sunshine filled days of summer. Luckily for you and the grapes, the nights cool down for easy resting for both of you. One of the wonders of visiting the region is to leave San Francisco during a cool, foggy summer day and drive to Napa for hot 90° weather.
June in Napa means average temperatures of 66° with an average high of 78°. Rainfall is practically non-existent with only 0.3 inches. July marks the beginning of truly hot weather with average temperatures in the 80s and 90s. Not too worry, the temperatures drop in the evening by as much as thirty degrees!
The fall is harvest time in Napa Valley. The days are somewhat cooler than summer, but you can still expect average daytime high temperatures in the 80s and sometimes the 90s. This is possibly the most beautiful time of year in Napa. Rainfall is still barely registering at 0.3 inches. October often sees the arrival of Indian Summer with temperatures still in the high 80s. Things start to cool down in November with the arrival of some rain and high temperatures in the upper 60s.
A few rainy spells put the vines into sleep mode, preparing them for another season of growth. Fields of bright yellow mustard are found throughout Napa Valley. "Winter" is a bit of a misnomer since temperatures very rarely go below freezing. You can expect patches of rain, but they are always followed with periods of warm sunshine.
The average temperature in Napa in December and January is in the high 40s with the average high in the upper 50s. During February the average temperature in Napa is 50° with 3.9 inches of rain. We love visiting at this time of year when the number of tourists is minimal and the wine growers seem to be more relaxed.
Winter's short season soon ends with the arrival of warm, spring days and visible buds on the vines. Mornings and evenings will still have a chill in the air, but afternoons will be warm and bright. March starts to bring warmer weather with an average of 70°. April and May sees even warmer weather with temperatures climbing into the 80s.
Check with Booking.com to find today's sale prices on hotel rooms in every neighborhood of SF. Save 20% to 30%… or even more!
No matter what time of year that you visit, remember to pack layers of clothes. Evenings are generally cool and a cozy sweater or pashmina is always a welcome wardrobe essential in Napa. During the winter bring an umbrella, waterproof footwear, and a warm coat. The dress code in Napa is generally casual but you are in Wine Country and you do want to look your best. With hot summer days, bring your sunscreen and a hat. No matter when you visit Napa Valley the weather will likely deliver California sunshine!
• 10 Top Napa Valley Wineries…
• Best Napa Restaurants…
• Napa Valley Wine Train…
• Napa Wine Tasting…
• Culinary Institute In Napa…
• Napa Valley Weather…
Don't Miss a Single San Francisco Travel Tip — Sign Up For Our Newsletter Today