Napa Valley Weather, When to Go and Climate Information

(Napa Valley, California - CA, USA)

Photo of unusual vineyard entrance in the Californian sunshineThe appealing climate enjoyed by Napa Valley strongly resembles that of the Mediterranean, with warm temperatures and sunny weather throughout the year. Both spring and summer have become very popular times to pay a visit to Napa Valley, when the skies are often blue and without any single clouds, and the nights are quite balmy. The southern side of the valley remains pleasantly cool at this time, due in no small part to its relative closeness to San Pablo Bay.

Those holidaying around Napa Valley during the dry summer climate can expect to be able to enjoy plenty of al fresco dining, hiking trails and many outdoor activities, particularly around the neighboring state parks of Annadel, Hood Mountain and Sugarloaf Ridge. Rainy weather rarely spoils a day, and the average annual precipitation levels average around 64 cm / 25 inches, with the winter months tending to be the wettest, although the eastern region of the valley is noticeably drier, being located away from the westerly mountains.

Further vineyard picture

Seasonal Climate Variations / When to Go

The coldest months in Napa Valley are predictably December and January, although daytime temperatures do tend to stay above 10°C / 50°F. Whilst the nights are colder, frosts are quite infrequent and snowy weather is considered unusual and quite rare.

The spring climate of Napa Valley sees temperatures gradually rising on an incremental basis from March through May. Days quickly become warm and pleasant, without being too hot for some, and so many choose to spend their spring vacation here.

Napa Valley Weather and Climate Chart (Averages)



12°C / 54°F
3°C / 37°F


15°C / 59°F
65°C / 149°F


18°C / 64°F
6°C / 43°F


22°C / 72°F
8°C / 46°F


26°C / 79°F
10°C / 50°F


31°C / 88°F
13°C / 55°F


34°C / 93°F
15°C / 59°F


33°C / 91°F
14°C / 57°F


30°C / 86°F
13°C / 55°F


25°C / 77°F
10°C / 50°F


17°C / 63°F
6°C / 43°F


11°C / 52°F
3°C / 37°F