Napa Weather in September: Temperature, Precipitation, Wind
Napa, United States in September experiences a Mediterranean climate characterized by warm, dry conditions. The average temperature hovers around 18.3°C (64.9°F), with daytime highs reaching 25.0°C (77.1°F) and nighttime lows dipping to 12.8°C (55.1°F). Visitors to Napa Valley’s renowned wineries enjoy comfortable temperatures throughout the day.
Humidity levels in September average 70.5%, contributing to the region’s ideal grape-growing conditions. Precipitation is scarce, with only 0.1 mm of rainfall expected and a mere 10% chance of rain on any given day. The area sees an average of 3 rainy days throughout the month, maintaining the dry conditions typical of Napa’s late summer season.
Wind patterns in Napa during September feature average wind speeds of 24.2 km/h (15 mph), with gusts reaching up to 33.4 km/h (20.8 mph). These breezes help moderate temperatures and contribute to the region’s pleasant microclimate. Atmospheric pressure remains steady at 1013.3 hPa, indicative of stable weather conditions.
Cloud cover in Napa averages 34.7% in September, resulting in mostly clear skies. The region boasts excellent visibility of 14.9 km (9.3 miles), allowing visitors to enjoy panoramic views of the surrounding vineyards and rolling hills. UV index levels are high at 8.9, necessitating sun protection for outdoor activities.
Sunrise occurs at approximately 6:51 AM, while sunset takes place around 7:16 PM, providing ample daylight hours for exploring Napa’s attractions. Popular destinations like the Napa Valley Wine Train and the Oxbow Public Market benefit from the pleasant September weather, offering visitors optimal conditions for outdoor dining and wine tasting experiences.
What is the temperature in Napa in September?
Average air temperature in Napa is 18.3°C (64.9°F) in September. The outside temperature in Napa feels like 18.3°C (64.9°F) on a typical September day. The highest average temperature during sunny days is 25°C (77.1°F) and feels like 24.9°C (76.9°F). The lowest average temperature after dark is 12.8°C (55.1°F) which feels like 12.8°C (55.1°F).
How hot is Napa in September?
The hot temperature in September in Napa rises to 28.7°C (83.7°F) on sunny days with low cloud coverage and 70.5% humidity. During hottest days of September it feels like 27.7 °C (81.9°F). The average maximum temp in Napa is 25°C (81.9°F) during day time in September.
How cold is Napa in September?
The coldest temp in Napa in September drops to 8.7°C (47.7°F) during the cold nights. With 24.2km/h (15mph) winds and 70.5% humidity it feels like 8.6°C (47.5°F) on the coldest nights. The average minimum temperature is 12.8°C (55.1°F) during night time in September.
Does it rain in Napa in September?
Yes, it rains for 3 days in Napa, United States in September averaging 0.1 mm of precipitation. Napa has a 10% chance for rain throughout the entire month of September.
How much does it rain in Napa throughout September?
Napa has 0.1 mm (0 inch) of rain per day on average in September. It rains for an average of 3 days out of the entire month.
Is Napa windy in September?
The average speed of wind in Napa, United States during September is 24.2km/h (15mph) and average windgust is 33.4km/h (20.7mph). On some days in September wind can reach up to 33.3km/h (20.7mph).
What is the direction of the wind in Napa in September?
Most days of September the wind is blowing from Southwest direction in Napa.
What are the humidity levels in Napa in September?
The average humidity levels in Napa in September are 70.5%. Daily humidity levels in Napa range from 65.7% to 76.1% during September.
How many hours of daylight are in Napa in September?
Napa has 12 hours 25 minutes of daylight in September on average. Sunset and sunrise times gradually change throughout the month. Sunrise in Napa in September is at 6:51:09 and the sunset is at 19:16:36.
What is the cloud coverage in Napa in September?
Clouds cover 34.7% of the sky on average throughout September in Napa. The cloud coverage ranges from 3.1% to 88.9% depending on the day of the month.
What is the UV level in September in Napa?
The average UV index in Napa is 8.9 in September. UV levels change throughout the month and range from 8 to 10.
What is the solar radiation in Napa in September?
The average solar radiation is 241.4 W/m2 (Watts per square meter) in Napa during September. However solar radiation levels change throughout the month and range from 174.1 W/m2 to 291.5 W/m2.
What is the solar energy during September in Napa?
The average solar energy during September in Napa is 20.9 MJ/m2 (megajoules per square metre). Solar energy ranges from 15 MJ/m2, to 25.2 MJ/m2 during September.
Are there severe weather risks in Napa in September?
Yes, there is a 10% risk for severe weather in Napa, United States in September.
What is the air pressure in Napa in September?
On average the air pressure in Napa in September is 1013.3 mb (millibars). Throughout the month the sea level pressure ranges from 1007.5 mb to 1018.6 mb.
What is the visibility in Napa in September?
The average daylight visibility in Napa in September is 14.9 km (9.2 miles). Depending on the precipitation the visibility ranges from 10.1 km (6.3 miles) to 16 km (9.9 miles) throughout September.
What is the dew point in Napa in September?
The average dew point in Napa during September is 12.4°C (54.3°F).
Where is the data for Napa climate in September coming from?
The climate data for Napa, California, United States in September is collected from the following weather stations.
- VACAVILLE NUT TREE AIRPORT, CA US
- NAPA CO AIRPORT, CA US
- PETALUMA MUNICIPAL AIRPORT, CA US
- FW1058 American Canyon CA US
- FW7520 Sonoma CA US
- KAPC
- KDVO
- KVCB