September weather forecast
Napa Soda Springs, CA

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Weather in September

The first month of the autumn, September, is still a warm month in Napa Soda Springs, California, with temperature in the range of an average high of 84°F (28.9°C) and an average low of 55.2°F (12.9°C).

Temperature

As Napa Soda Springs steps into September, the average high-temperature holds at a warm 84°F (28.9°C), hinting at a minor fluctuation from the prior month. The nighttime temperature during September exhibits a clear drop from daytime highs, settling at a cool 55.2°F (12.9°C).

Heat index

In September, the average heat index is computed to be a hot 86°F (30°C). If one continues to be active during exposure, it might cause tiredness and subsequent heat cramps.
From a standpoint of the heat index, values pertain to shaded conditions and mild breezes. Exposure to the direct sun could elevate the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', evaluates the perceived heat by adding the effect of moisture in the air. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. It is noteworthy to mention that direct sunlight exposure can augment the felt temperature, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are of high significance for children. Kids frequently fail to realize the necessity for resting and hydrating. Thirst is an advanced indication of dehydration - hence, maintaining hydration, especially during extended physical activities, becomes essential.

Humidity

The least humid month is September, with an average relative humidity of 54%.

Rainfall

In September, in Napa Soda Springs, California, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, there are 77.8 rainfall days, and 16.02" (407mm) of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of September, sunrise is at 6:39 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine in Napa Soda Springs is 11.1h.

UV index

In Napa Soda Springs, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum UV index of 5 during September leads to these instructions:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. When the Sun is at its strongest around midday, find shade and limit exposure. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is September in Napa Soda Springs?

The average high-temperature and low-temperature during September are 84°F (28.9°C) and 55.2°F (12.9°C) respectively. In September, the average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines air temperature and relative humidity, is computed to be 86°F (30°C).

What is the least humid month in Napa Soda Springs?

September is the least humid month in Napa Soda Springs, California, with an average relative humidity of 54%.

What is the average humidity in September in Napa Soda Springs?

In September, the average relative humidity in Napa Soda Springs, California, is 54%.

How many days does it rain in September in Napa Soda Springs?

In September, in Napa Soda Springs, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated.

What is the average length of the day in September in Napa Soda Springs?

In September, the average day length is 12h and 25min.

What time are sunrise and sunset in September in Napa Soda Springs?

On the first day of September in Napa Soda Springs, sunrise is at 6:39 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:04 am and sunset at 6:52 pm PDT.

How many hours of sunshine does Napa Soda Springs have in September?

In Napa Soda Springs, the average sunshine duration in September is 11.1h.

How high is the UV index in September in Napa Soda Springs?

In September, the average daily maximum UV index in Napa Soda Springs, California, is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Napa Soda Springs, CA

Average temperature in September - Napa Soda Springs, CA
  • Average high temperature in September: 84°F

The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is December (54.5°F).

  • Average low temperature in September: 55.2°F

The month with the highest average low temperature is August (55.4°F).
The coldest month (with the lowest average low temperature) is December (40.1°F).

Average pressure in September
Napa Soda Springs, CA

Average pressure in September - Napa Soda Springs, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).

Average wind speed in September
Napa Soda Springs, CA

Average wind speed in September - Napa Soda Springs, CA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is May (6mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).

Average humidity in September
Napa Soda Springs, CA

Average humidity in September - Napa Soda Springs, CA
  • Average humidity in September: 54%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (54%).

Average rainfall in September
Napa Soda Springs, CA

Average rainfall in September - Napa Soda Springs, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in September
Napa Soda Springs, CA

Average rainfall days in September - Napa Soda Springs, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (13.9 days).
The month with the least rainy days is August (0.9 days).

Average daylight in September /
Average sunshine in September
Napa Soda Springs, CA

Average daylight in September / Average sunshine in September - Napa Soda Springs, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 11h and 1min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).

Average sunshine days in September
Napa Soda Springs, CA

Average sunshine days in September - Napa Soda Springs, CA
  • Average sunshine days in September: 26.9 days

The month with the most sunshine days is July (29.4 days).
The month with the least sunshine days is March (15.8 days).

Average UV index in September
Napa Soda Springs, CA

Average UV index in September - Napa Soda Springs, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in September
Napa Soda Springs, CA

Average cloud cover in September - Napa Soda Springs, CA
  • Average cloud cover in September: 9

The month with the most cloud cover is March (Cloud cover 40).
The month with the least cloud cover is July (Cloud cover 6).

Average visibility in September
Napa Soda Springs, CA

Average visibility in September - Napa Soda Springs, CA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

Napa Soda Springs, California, USA

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