Last updated: February 24, 2025
In December, Napa, United States, embraces a mild climate characterized by a maximum temperature of 24°C (75°F) and an average of 10°C (50°F), providing a comfortable backdrop for winter activities. As the temperatures dip to a chilly minimum of 0°C (32°F), the region experiences 91 mm (3.6 in) of precipitation over 9 days, contributing to its lush landscapes. With humidity levels hovering around 83%, visitors can expect a refreshing, crisp atmosphere that adds to Napa's enchanting winter charm.
In Napa, December showcases a cool yet pleasant climate, with temperatures ranging from a minimum of 0°C (32°F) to a comfortable maximum of 24°C (75°F). The average temperature settles at 10°C (50°F), indicating a steady chill as the region transitions into winter. This month stands out in its temperateness, as it marks a slight dip compared to the warmer months preceding it, yet remains milder than many other winter destinations. The trend from November to December reveals a gradual drop in minimum temperatures, while maximums still tease a moderate warmth. Overall, Napa's December offers a delightful blend of crisp air and sunny days, perfect for exploring its renowned vineyards or savoring the local cuisine in cozy settings.
In Napa, December typically ushers in a significant increase in precipitation, with an average of 91 mm (3.6 in) falling over 9 days. This marks the transition from the dry summer months to the wetter winter season, helping to replenish local water sources. Compared to the earlier drought-like conditions of July and August, which recorded 0 mm of rain, December's rainfall is a welcome relief. Interestingly, this month generally experiences more rainfall than both October and November, which receive 29 mm (1.1 in) and 43 mm (1.7 in) respectively. This trend suggests that as the year closes, Napa’s weather pattern shifts distinctly, providing essential moisture for the region’s famous vineyards and natural surroundings.
In Napa, California, December brings a humidity level of 83%, maintaining a trend of relatively high moisture in the air as the year wraps up. The humidity in December closely mirrors that of earlier months, particularly January and February, both at 84%, and hints at a notable consistency through the late fall season, where November also shares a similar figure. As the year transitions from the dry summer months—with July and August dipping to just 44% and 36%—the increased humidity during these colder months signals the onset of winter's chill, creating an inviting atmosphere for those seeking a cozy escape in Napa's celebrated wine country.
In December, Napa experiences a moderate UV Index of 3, similar to the beginning of the year, with a burn time of 30 minutes. This trend of lower UV levels contrasts sharply with the summer months, where readings soar to extreme levels, peaking at 11 in both June and July. As the year progresses, UV exposure intensity gradually declines from spring's high of 9 in April to a more manageable index by December. Residents and visitors can enjoy outdoor festivities during this festive month while remaining aware of their sun exposure. For detailed information, explore the Napa UV Index.
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In Napa, United States, December ushers in a gentle decline in sunshine hours, with an average of 185 hours illuminating the month. This is a seasonal shift as the region transitions from the sun-soaked peaks of July and June, which boast impressive totals of 394 and 384 hours respectively. As autumn arrives, sunshine begins to recede, dropping notably in November to 220 hours, before slightly tapering off in December. Despite this decline, the month still offers a generous amount of sunlight, making Napa's winter months a unique and charming time to savor the picturesque vineyards under soft winter sun.
As December rolls into Napa, the likelihood of basking in sunny weather takes a notable dip, dropping to just 31%. This marks a significant decline from the sun-soaked days of late spring and early summer, where the chances soared above 80%. Reflecting on the year's progression, the trend shows a steady increase in sunny days from January's modest 38% all the way to May and June's peak sunshine, before tapering off again in the fall. By December, the cozy embrace of winter sets in, making those sunny moments feel even more special as the vineyards and hills transition into a serene landscape of muted hues. While the likelihood of sunshine may not be high, Napa still offers a charming winter ambiance filled with cozy gatherings and seasonal delights.
As December rolls in, Napa experiences the shortest daylight of the year, with just 9 hours of sunlight each day. This marks a significant drop from the long, sun-drenched days of summer, where daylight peaked at 14 hours during June and July. The gradual decline in daylight begins in late summer, transitioning through the fall months when September and October offer 12 and 11 hours, respectively. November sees a further reduction to 10 hours before December completes the cycle of diminishing light. This pattern highlights a seasonal rhythm, as Napa shifts from the vibrant brightness of spring and summer to the cozy ambiance of winter, perfectly framing the region's rich agricultural cycles and inviting festive pursuits.
As December settles over Napa, the average wind speed gently returns to 2.0 m/s (5 mph), mirroring the calm seen in January. This month wraps up the year with a noticeable shift in wind patterns; after peaking in early summer with a maximum of 3.3 m/s (7 mph) in June, the winds gradually wane towards winter. Overall, the trend throughout the year reveals a steady increase in wind speed from January through May, followed by a slight decline as the warmer months give way to cool, crisp air. November marks the calmest month, dipping to 1.6 m/s (4 mph), but December brings a refreshing balance, inviting a tranquil end to the year while still carrying hints of the breezy summer days that have passed.
The weather in Napa changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of December's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Napa and find detailed weather information for every month.
In December, temperatures range from a minimum of 0°C (32°F) to a maximum of 24°C (75°F), with an average of 10°C (50°F). The month sees about 91 mm (3.6 in) of precipitation over 9 days, accompanied by a relatively high humidity level of 83%.
In contrast, January experiences slightly cooler temperatures, with a minimum of -2°C (29°F) and a maximum of 25°C (77°F), while still maintaining the same average of 10°C (50°F). It also tends to be wetter, with 119 mm (4.7 in) of precipitation spread across 8 days and humidity rising to 84%.
For more detailed insights, you can check out the weather specifics here: Napa weather in January.
December and February exhibit distinct weather patterns, despite being close in calendar proximity. December typically sees milder temperatures with a minimum of 0°C (32°F) and a maximum of 24°C (75°F), resulting in an average of 10°C (50°F). In contrast, February offers slightly cooler mornings with a minimum temperature of -1°C (30°F), while daytime highs can reach 27°C (80°F), leading to a marginally higher average of 11°C (53°F). Precipitation is more pronounced in February, with 113 mm (4.5 in) of rain over 7 days, compared to December's 91 mm (3.6 in) over 9 days. Humidity levels are quite similar, hovering around 83% in December and 84% in February. For more details on February weather in Napa, you can check out Napa weather in February.
In December, temperatures range from a minimum of 0°C (32°F) to a maximum of 24°C (75°F), with an average of 10°C (50°F). The month sees a total precipitation of 91 mm (3.6 in) over about 9 days, accompanied by a humidity level of 83%. In contrast, March experiences slightly warmer conditions with temperatures starting at a minimum of 1°C (34°F) and peaking at 30°C (87°F), averaging 12°C (55°F). Precipitation is slightly lower at 81 mm (3.2 in) over the same number of days, while humidity remains consistent at 83%. For a deeper look at the weather specifics for March, visit Napa weather in March.
December weather is characterized by cooler temperatures, with a minimum of 0°C (32°F) and an average of 10°C (50°F), reaching a maximum of 24°C (75°F). The month sees significant rainfall, accumulating 91 mm (3.6 in) over approximately 9 days, and maintaining a high humidity level of 83%. In contrast, April experiences milder and more pleasant conditions, with temperatures ranging from a minimum of 3°C (38°F) to a maximum of 33°C (92°F) and an average temperature of 15°C (60°F). There is considerably less precipitation, totaling just 33 mm (1.3 in) over about 5 days, along with slightly lower humidity at 81%. For more detailed information, you can check Napa weather in April.
December weather features a cooler range, with temperatures varying from a chilly minimum of 0°C (32°F) to a maximum of 24°C (75°F), while the average settles at around 10°C (50°F). The month is characterized by higher humidity at 83% and considerable precipitation, totaling 91 mm (3.6 in) over approximately 9 days. In contrast, May brings a more temperate climate, where temperatures range from a milder minimum of 5°C (41°F) to a sweltering maximum of 37°C (99°F), with an average of 18°C (64°F). This month experiences significantly less precipitation at 19 mm (0.8 in) over just 2 days, coupled with a lower humidity of 74%. For more insights, check out Napa weather in May.
December experiences a cooler climate with temperatures ranging from a chilly minimum of 0°C (32°F) to a comfortable maximum of 24°C (75°F), accompanied by an average temperature of 10°C (50°F). This month also brings significant precipitation, averaging 91 mm (3.6 in) over about 9 days, and humidity levels remain quite high at 83%. In contrast, June offers a much warmer atmosphere with minimum temperatures of 10°C (51°F) and maximums soaring to 41°C (106°F), paired with a pleasant average of 21°C (70°F). Notably, June is dry, with only 2 mm (0.1 in) of precipitation and no rainy days, and the humidity drops to 64%. For a detailed look at the summer conditions, you can explore more about Napa weather in June.
December and July present strikingly different weather patterns. In December, temperatures range from a chilly 0°C (32°F) at night to a mild max of 24°C (75°F), with an average of 10°C (50°F). This month also sees considerable rainfall, with 91 mm (3.6 inches) spread over 9 days and a high humidity level of 83%. In stark contrast, July boasts warmer temperatures, with nighttime lows of 11°C (53°F) and daytime highs soaring to a scorching 40°C (104°F), averaging 21°C (70°F). Interestingly, July is characterized by its dryness, as there is no recorded precipitation, and the humidity drops to a comfortable 44%. For more specific insights, you can check Napa weather in July.
December and August present stark contrasts in weather. In December, temperatures typically range from a minimum of 0°C (32°F) to a maximum of 24°C (75°F), with an average of 10°C (50°F). This month is also marked by frequent precipitation, accumulating to 91 mm (3.6 inches) over about 9 days, contributing to a high humidity level of 83%. In contrast, August boasts much warmer conditions, with temperatures ranging from a minimum of 12°C (53°F) to an impressive maximum of 42°C (108°F) and an average of 21°C (71°F). Remarkably, August experiences no precipitation at all, resulting in a much drier atmosphere with a humidity level of only 36%. For more details on August weather, you can check Napa weather in August.
December and September present a stark contrast in weather conditions. In December, temperatures range from a chilly 0°C (32°F) at night to a comfortable 24°C (75°F) during the day, accompanied by significant precipitation of 91 mm (3.6 in) over about nine days, leading to an average humidity of 83%. In sharp contrast, September boasts much warmer temperatures, with nighttime lows around 8°C (46°F) and daytime highs soaring up to 44°C (111°F). Notably, precipitation is virtually non-existent, with only 1 mm recorded and no rainy days, resulting in a much drier atmosphere with just 44% humidity. For more details, visit Napa weather in September.
December weather tends to be cooler and wetter compared to October. While December sees minimum temperatures dropping to around 0°C (32°F) and an average of 10°C (50°F), October enjoys milder conditions with minimums of 4°C (40°F) and an average of 18°C (65°F). Rainfall is significantly more frequent in December, averaging 91 mm (3.6 in) over 9 days, in stark contrast to October's 29 mm (1.1 in) over just 2 days. Humidity levels also rise in December to 83%, while October remains more comfortable at 65%. For more insights into October's specific conditions, check out Napa weather in October.
When comparing the weather between November and December, November typically features milder temperatures, with an average of 13°C (56°F) and maximums reaching up to 30°C (86°F). In contrast, December experiences cooler conditions, averaging 10°C (50°F) and peaking at 24°C (75°F). Additionally, December sees an increase in precipitation, totaling 91 mm (3.6 in) over 9 days, compared to November's 43 mm (1.7 in) over just 5 days. Both months have similar humidity levels, with November at 84% and December slightly higher at 83%. For more detailed information, you can check Napa weather in November.
As December rolls into Napa, the weather showcases a unique blend of warmth and chill, distinguishing it from the more temperate months. With daytime highs offering a pleasant 24°C, it’s perfect for enjoying the scenic vineyards, yet evenings can dip to a brisk 0°C, reminding us that winter has arrived. The higher humidity levels create a cozy atmosphere, while an average of 9 rainy days contributes to the region's lush landscape. This contrast makes December an ideal time to experience Napa's serene beauty, complemented by fewer crowds. For a detailed insight into how December fits into Napa's overall climate, be sure to check out Napa Climate.