September weather forecast
Charter Oak, CA

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Weather in September

The first month of the autumn, September, is also a hot month in Charter Oak, California, with temperature in the range of an average low of 63.3°F (17.4°C) and an average high of 86.7°F (30.4°C).

Temperature

With the advent of September, Charter Oak experiences an average high-temperature of a still tropical 86.7°F (30.4°C), mirroring a close resemblance to the previous month. During September, the nighttime temperature presents a clear descent from the daily peaks, falling to an average of 63.3°F (17.4°C).

Heat index

In September, the average heat index is computed to be a hot 87.8°F (31°C). Long-standing exposure and activity could induce a feeling of tiredness and lead to heat cramps.
Research indicates the heat index considers values in shaded locales and with light winds. Exposure to the direct sun might augment heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is derived by integrating air temperature with the existing relative humidity to express the perceived warmth. Factors encompassing physical activity, clothing, and metabolic differences have a role in shaping the individual's impression of temperature. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children frequently underestimate the necessity to rest and hydrate. Thirst is a late sign of dehydration - thus, it is vital to stay hydrated, particularly during lengthy physical exercises.

Humidity

The average relative humidity in September in Charter Oak is 46%.

Rainfall

In September, in Charter Oak, the rain falls for 2.5 days. Throughout September, 0.12" (3mm) of precipitation is accumulated. Throughout the year, in Charter Oak, California, there are 45.2 rainfall days, and 6.5" (165mm) of precipitation is accumulated.

Daylight

In Charter Oak, the average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:25 am and sunset at 7:16 pm. On the last day of September, in Charter Oak, sunrise is at 6:45 am and sunset at 6:36 pm PDT.

Sunshine

In September, the average sunshine in Charter Oak, California, is 10.7h.

UV index

In September, the average daily maximum UV index is 6. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index of 6 during September leads to these instructions:
Evade overexposure. Individuals with fair skin risk burning in under 20 minutes. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in Charter Oak in September?

The high-temperature, in September, in Charter Oak, records 86.7°F (30.4°C), while the low-temperature is 63.3°F (17.4°C). In September, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines relative humidity and air temperature, is computed to be 87.8°F (31°C).

What is the average humidity in September in Charter Oak?

The average relative humidity in September in Charter Oak, California, is 46%.

How many days does it rain in September in Charter Oak?

In September, the rain falls for 2.5 days. Throughout September, 0.12" (3mm) of precipitation is accumulated.

What is the average length of the day in September in Charter Oak?

The average day length in September in Charter Oak, California, is 12h and 22min.

When are sunrise and sunset in September in Charter Oak?

On the first day of September in Charter Oak, California, sunrise is at 6:25 am and sunset at 7:16 pm. On the last day of the month, sunrise is at 6:45 am and sunset at 6:36 pm PDT.

How many hours of sunshine does Charter Oak have in September?

The average sunshine duration in September is 10.7h.

What is the UV index intensity in September in Charter Oak?

In Charter Oak, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health risk from 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
Charter Oak, CA

Average temperature in September - Charter Oak, CA
  • Average high temperature in September: 86.7°F

The warmest month (with the highest average high temperature) is August (89.4°F).
The month with the lowest average high temperature is December (62.4°F).

  • Average low temperature in September: 63.3°F

The month with the highest average low temperature is August (64.9°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

Average pressure in September
Charter Oak, CA

Average pressure in September - Charter Oak, CA
  • Average pressure in September: 29.88"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

Average wind speed in September
Charter Oak, CA

Average wind speed in September - Charter Oak, CA
  • Average wind speed in September: 4.3mph

The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest month (with the lowest average wind speed) is September (4.3mph).

Average humidity in September
Charter Oak, CA

Average humidity in September - Charter Oak, CA
  • Average humidity in September: 46%

The months with the highest relative humidity are March and May (55%).
The months with the lowest relative humidity are August and November (45%).

Average rainfall in September
Charter Oak, CA

Average rainfall in September - Charter Oak, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (1.46").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in September
Charter Oak, CA

Average rainfall days in September - Charter Oak, CA
  • Average rainfall days in September: 2.5 days

The month with the highest number of rainy days is March (6.3 days).
The month with the least rainy days is June (1.2 days).

Average daylight in September /
Average sunshine in September
Charter Oak, CA

Average daylight in September / Average sunshine in September - Charter Oak, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).

  • Average sunshine in September: 10h and 4min

The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 7h and 0min).

Average sunshine days in September
Charter Oak, CA

Average sunshine days in September - Charter Oak, CA
  • Average sunshine days in September: 25.5 days

The month with the most sunshine days is June (27.8 days).
The month with the least sunshine days is February (22 days).

Average UV index in September
Charter Oak, CA

Average UV index in September - Charter Oak, CA
  • Average UV index in September: 6

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

Average cloud cover in September
Charter Oak, CA

Average cloud cover in September - Charter Oak, CA
  • Average cloud cover in September: 6

The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

Average visibility in September
Charter Oak, CA

Average visibility in September - Charter Oak, 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).

Charter Oak, California, USA

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