Napa Weather in December: Temperature, Precipitation, Wind
Napa, United States in December experiences a mild Mediterranean climate with cool temperatures and occasional rainfall. The average temperature hovers around 10.6°C (51.0°F), with daytime highs reaching 15.9°C (60.7°F) and nighttime lows dipping to 6.0°C (42.8°F). Residents and visitors feel the chill more acutely during early mornings and evenings, as the average feels-like temperature drops to 5.1°C (41.2°F).
December brings increased precipitation to Napa Valley, with an average of 3.1 mm of rainfall throughout the month. Rain falls on approximately 15 days, covering 14.9% of the time. The probability of precipitation stands at 48.4%, making umbrellas and raincoats essential accessories for exploring the famous vineyards and wineries.
Wind patterns in Napa during December are notable, with average wind speeds of 18.3 km/h and gusts reaching up to 28.6 km/h. These breezes contribute to the region’s microclimate, influencing grape cultivation and wine production. The atmospheric pressure averages 1018.6 hPa, indicating stable weather conditions.
Cloud cover in Napa averages 43.7% in December, allowing for periods of sunshine interspersed with overcast skies. The UV index remains moderate at 4.1, while visibility extends to 13.3 km, offering clear views of the surrounding Napa Valley landscape on non-rainy days.
December days in Napa are short, with sunrise occurring around 7:18 AM and sunset at approximately 4:51 PM. The reduced daylight hours contribute to the cooler temperatures and create a cozy atmosphere in the region’s renowned restaurants and tasting rooms.
Humidity levels in Napa during December are relatively high, averaging 80.0%. The moist air combines with cool temperatures to create ideal conditions for fog formation, which blankets the valley in the early mornings, gradually dissipating as the day progresses.
What is the temperature in Napa in December?
Average air temperature in Napa is 10.6°C (51°F) in December. The outside temperature in Napa feels like 10.3°C (50.5°F) on a typical December day. The highest average temperature during sunny days is 15.9°C (60.7°F) and feels like 15.9°C (60.7°F). The lowest average temperature after dark is 6°C (42.8°F) which feels like 5.1°C (41.2°F).
How hot is Napa in December?
The hot temperature in December in Napa rises to 20.4°C (68.7°F) on sunny days with low cloud coverage and 80% humidity. During hottest days of December it feels like 20.4 °C (68.7°F). The average maximum temp in Napa is 15.9°C (68.7°F) during day time in December.
How cold is Napa in December?
The coldest temp in Napa in December drops to -0.1°C (31.8°F) during the cold nights. With 18.3km/h (11.4mph) winds and 80% humidity it feels like -3.1°C (26.4°F) on the coldest nights. The average minimum temperature is 6°C (42.8°F) during night time in December.
Does it rain in Napa in December?
Yes, it rains for 15 days in Napa, United States in December averaging 3.1 mm of precipitation. Napa has a 48.4% chance for rain throughout the entire month of December.
How much does it rain in Napa throughout December?
Napa has 3.1 mm (0.12 inch) of rain per day on average in December. It rains for an average of 15 days out of the entire month.
Is Napa windy in December?
The average speed of wind in Napa, United States during December is 18.3km/h (11.4mph) and average windgust is 28.6km/h (17.8mph). On some days in December wind can reach up to 34.7km/h (21.6mph).
What is the direction of the wind in Napa in December?
Most days of December the wind is blowing from Southeast direction in Napa.
What are the humidity levels in Napa in December?
The average humidity levels in Napa in December are 80%. Daily humidity levels in Napa range from 50.9% to 91% during December.
How many hours of daylight are in Napa in December?
Napa has 9 hours 32 minutes of daylight in December on average. Sunset and sunrise times gradually change throughout the month. Sunrise in Napa in December is at 7:18:29 and the sunset is at 16:51:24.
What is the cloud coverage in Napa in December?
Clouds cover 43.7% of the sky on average throughout December in Napa. The cloud coverage ranges from 0% to 99% depending on the day of the month.
What is the UV level in December in Napa?
The average UV index in Napa is 4.1 in December. UV levels change throughout the month and range from 1 to 6.
What is the solar radiation in Napa in December?
The average solar radiation is 81.7 W/m2 (Watts per square meter) in Napa during December. However solar radiation levels change throughout the month and range from 14.8 W/m2 to 128 W/m2.
What is the solar energy during December in Napa?
The average solar energy during December in Napa is 7.1 MJ/m2 (megajoules per square metre). Solar energy ranges from 1.4 MJ/m2, to 11 MJ/m2 during December.
Are there severe weather risks in Napa in December?
Yes, there is a 10% risk for severe weather in Napa, United States in December.
What is the air pressure in Napa in December?
On average the air pressure in Napa in December is 1018.6 mb (millibars). Throughout the month the sea level pressure ranges from 1006.5 mb to 1026.6 mb.
What is the visibility in Napa in December?
The average daylight visibility in Napa in December is 13.3 km (8.3 miles). Depending on the precipitation the visibility ranges from 5.4 km (3.4 miles) to 16 km (9.9 miles) throughout December.
What is the dew point in Napa in December?
The average dew point in Napa during December is 6.9°C (44.4°F).
Where is the data for Napa climate in December coming from?
The climate data for Napa, California, United States in December is collected from the following weather stations.
- VACAVILLE NUT TREE AIRPORT, CA US
- NAPA CO AIRPORT, CA US
- PETALUMA MUNICIPAL AIRPORT, CA US
- FW7520 Sonoma CA US
- KAPC
- KDVO
- KVCB