Napa Valley Climate


 



In short, it's Californian—very Mediterranean. It's a great place to be a grape, and a very good one to be a human.

The Napa Valley is far enough inland to escape most of the fog that lingers along the California coast during summer. Yet, unlike California's Central Valley, it's close enough to the ocean to take advantage of the cooling effect of that fog.

It can get hot in the summer, but usually not too hot. We can expect a week or two during the summer when the temperatures are around 100° F, usually in July or August, which are the hottest months. The southern end of the valley, where the city of Napa is located, is cooler. It's closer to the northern tip of San Francisco Bay, known as San Pablo Bay. Winds come through the Golden Gate, move upward and cool off the southern end of Napa County as far as Yountville. They also come over the hills from the west and Sonoma County's coast.

North of Yountville the valley doglegs to the left (west). The late afternoon wind from the bay doesn't make the turn, so the St. Helena and Calistoga areas tend to be much warmer. During the summer, the temperature upvalley can be ten to twenty degrees (F) warmer than in the Napa area.

In the winter, it rains—but not a lot. The county's average annual rainfall for the entire year is less than 24 inches, with over half of that in December, January and February. And it's not unusual to have temperatures in the 70s and 80s (F) around Christmas time.

The western side of the valley—the Mayacamas Mountains—gets more rain, apparent by the redwood and fir forests and numerous streams and waterfalls. The eastern side of the valley—the Vacas Mountains (named for the Vaca family that settled here in 1841)—tends to be more desert-like in many areas, with scrub brush and even cactus.

Average Temperatures by Season

Season

Minimum (°F)

Maximum(°F)

Spring

64

78

Summer

81

92

Fall

74

85

Winter

61

72

Average Temperatures by Month

City of Napa  

Located at 38.30°N 122.28°W.

Height 6m / 19 feet above sea level.

Month

Fahrenheit

Celsius

Jan

46.8

8.2

Feb

50.5

10.3

Mar

52.9

11.6

Apr

56.1

13.4

May

60.3

15.7

Jun

64.9

18.3

Jul

66.9

19.4

Aug

66.6

19.2

Sep

65.8

18.8

Oct

61.3

16.3

Nov

53.6

12.0

Dec

47.7

8.7

Year

57.7

14.3

City of St. Helena

Located at 38.50° N 122.46° W.

Height 68m / 223 feet above sea level

Month

Fahrenheit

Celsius

Jan

46.0

7.7

Feb

50.2

10.1

Mar

52.3

11.3

Apr

56.3

13.5

May

62.4

16.9

Jun

68.0

20.0

Jul

71.1

21.3

Aug

70.7

21.5

Sep

67.6

19.8

Oct

61.7

16.5

Nov

52.3

11.3

Dec

46.6

8.1

Year

58.8

14.9

Average Rainfall for Napa County

Month

MM

Inches

Jan

117.3

4.6

Feb

84.8

3.3

Mar

79.5

3.1

Apr

50.2

2.0

May

13.6

0.5

Jun

5.9

0.2

Jul

0.4

0.0

Aug

3.1

0.1

Sep

6.0

0.2

Oct

32.6

1.3

Nov

72.3

2.8

Dec

132.9

5.2

Year

599.3

23.6

 

Info from: http://www.napanow.com/climate.html








































Terry and Chris Wunderlich

Terry Wunderlich
terry@napawunder.com
707.486.6388

Chris Wunderlich
chris@napawunder.com
707.529.0987


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