September weather forecast
American Canyon, CA

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Weather in September

September, the first month of the autumn in American Canyon, is still a warm month, with temperature in the range of an average low of 56.3°F (13.5°C) and an average high of 81.7°F (27.6°C).

Temperature

September's advent notes a subtle adjustment in average high-temperature to a still warm 81.7°F (27.6°C) from August. Contrasted against daytime highs, American Canyon records an average nighttime low of 56.3°F (13.5°C) in September.

Heat index

During September, the heat index is evaluated at 84.2°F (29°C). Prolonged exposure combined with continuous activity could lead to exhaustion, and possibly heat cramps.
Heat index readings emphasize conditions of light breezes and shaded spots. Exposure to unobstructed sunshine could lead to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'apparent temperature', combines both the air temperature and the humidity level to give a perceived human temperature. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. Under direct sun rays, the felt temperature might be heightened, with the heat index increasing by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Children frequently do not understand the need for recuperation and hydration. Thirst, being a late manifestation of dehydration, underlines the need to hydrate frequently, especially when engaging in prolonged physical exercises.

Humidity

The least humid month is September, with an average relative humidity of 58%.

Rainfall

In American Canyon, in September, it is raining for 2.5 days, with typically 0.08" (2mm) of accumulated precipitation. In American Canyon, during the entire year, the rain falls for 68.2 days and collects up to 11.93" (303mm) of precipitation.

Daylight

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

Sunshine

In September, the average sunshine is 11.1h.

UV index

In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the average person.
Note: In September, the maximum UV index of 5 transforms into these recommendations:
Make use of precautions - It is urged to ward off sun damage. To protect against the Sun's most potent rays, avoid direct exposure around midday. During bright days, sunglasses that offer UVA and UVB defense are recommended.
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Frequently asked questions

What are September temperatures in American Canyon?

During September, American Canyon experiences an average high-temperature of 81.7°F (27.6°C) and a low-temperature of 56.3°F (13.5°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which calculates the temperature value influenced by the moisture in the air, in September is evaluated at 84.2°F (29°C).

What is the least humid month in American Canyon?

With an average relative humidity of 58%, September is the least humid month in American Canyon.

What is the average humidity in September in American Canyon?

The average relative humidity in September in American Canyon is 58%.

How many days does it rain in September in American Canyon?

In American Canyon, California, in September, it is raining for 2.5 days, with typically 0.08" (2mm) of accumulated precipitation.

What is the average length of the day in September in American Canyon?

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

When is the sunrise / sunset in September in American Canyon?

On the first day of September in American Canyon, California, 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 American Canyon have in September?

In September, the average sunshine duration in American Canyon is 11.1h.

What is the UV index intensity in September in American Canyon?

In September, the average daily maximum UV index in American Canyon, California, is 5. A UV Index reading of 3 to 5 represents 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
American Canyon, CA

Average temperature in September - American Canyon, CA
  • Average high temperature in September: 81.7°F

The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is December (54.9°F).

  • Average low temperature in September: 56.3°F

The month with the highest average low temperature is August (56.5°F).
The coldest months (with the lowest average low temperature) are January and December (42.3°F).

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Average pressure in September
American Canyon, CA

Average pressure in September - American Canyon, CA
  • Average pressure in September: 29.92"Hg

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

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Average wind speed in September
American Canyon, CA

Average wind speed in September - American Canyon, CA
  • Average wind speed in September: 5.1mph

The windiest month (with the highest average wind speed) is May (6.6mph).
The calmest month (with the lowest average wind speed) is November (4.5mph).

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Average humidity in September
American Canyon, CA

Average humidity in September - American Canyon, CA
  • Average humidity in September: 58%

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is September (58%).

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Average rainfall in September
American Canyon, CA

Average rainfall in September - American Canyon, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (2.32").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
American Canyon, CA

Average rainfall days in September - American Canyon, CA
  • Average rainfall days in September: 2.5 days

The month with the highest number of rainy days is March (11.9 days).
The month with the least rainy days is August (0.9 days).

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Average daylight in September /
Average sunshine in September
American Canyon, CA

Average daylight in September / Average sunshine in September - American Canyon, 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 36min).

  • Average sunshine in September: 11h and 1min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

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Average sunshine days in September
American Canyon, CA

Average sunshine days in September - American Canyon, CA
  • Average sunshine days in September: 26.8 days

The months with the most sunshine days are July and August (29.1 days).
The month with the least sunshine days is March (18.3 days).

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Average UV index in September
American Canyon, CA

Average UV index in September - American Canyon, 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).

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Average cloud cover in September
American Canyon, CA

Average cloud cover in September - American Canyon, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 7).

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Average visibility in September
American Canyon, CA

Average visibility in September - American Canyon, 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).

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American Canyon, California, USA

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