September weather forecast
Twin Peaks, CA

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Weather in September

September, the first month of the autumn in Twin Peaks, is still a warm month, with an average temperature fluctuating between 62.4°F (16.9°C) and 85.8°F (29.9°C).

Temperature

The initiation of September sees an average high-temperature of a moderately hot 85.8°F (29.9°C), showing minor variations from the previous month. With a notable disparity from daily peak temperatures, the average low-temperature in Twin Peaks settles at an enjoyable 62.4°F (16.9°C) throughout September.

Humidity

In September, the average relative humidity is 39%.

Rainfall

In Twin Peaks, California, in September, during 2.6 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. Throughout the year, there are 51.8 rainfall days, and 6.69" (170mm) of precipitation is accumulated.

Snowfall

January, March through December are months without snowfall.

Daylight

The average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:22 am and sunset at 7:14 pm. On the last day of September, sunrise is at 6:43 am and sunset at 6:33 pm PDT.

Sunshine

In September, the average sunshine is 10.7h.

UV index

In Twin Peaks, the average daily maximum UV index in September is 6. A UV Index estimate of 6 to 7 represents a high health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum high daily UV index of 6 during September translates into the following directions:
Undertake protective measures and comply with sun safety rules. Shielding against skin and eye damage is essential. Avoid direct Sun exposure and seek shade between 10 a.m. and 4 p.m., when UV radiation is at its peak, but keep in mind that not all shade structures provide complete protection. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses.
Updated: Aug 15, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Is it hot during September?

An average high-temperature, in September, in Twin Peaks, is 85.8°F (29.9°C) and the average low-temperature is 62.4°F (16.9°C). In June, the average heat index (a.k.a. 'felt air temperature', 'real feel'), which factors the actual air temperature with the relative humidity, is evaluated at 84.2°F (29°C).

What is the average humidity in September?

In Twin Peaks, the average relative humidity in September is 39%.

How much does it rain in Twin Peaks in September?

In Twin Peaks, in September, during 2.6 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

When it does not snow?

January, March through December are months without snowfall.

How many hours of daylight does Twin Peaks have in September?

In Twin Peaks, the average day length in September is 12h and 22min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:22 am and sunset at 7:14 pm. On the last day of the month, sunrise is at 6:43 am and sunset at 6:33 pm PDT.

How long on average sun shines in September?

The average sunshine duration in September is 10.7h.

What is the UV index reading in September?

In September, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Twin Peaks, CA

Average temperature in September - Twin Peaks, CA
  • Average high temperature in September: 85.8°F

The warmest month (with the highest average high temperature) is August (90.9°F).
The month with the lowest average high temperature is December (57.7°F).

  • Average low temperature in September: 62.4°F

The month with the highest average low temperature is August (66.6°F).
The coldest months (with the lowest average low temperature) are February and December (41.5°F).

Average pressure in September
Twin Peaks, CA

Average pressure in September - Twin Peaks, CA
  • Average pressure in September: 29.86"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in September
Twin Peaks, CA

Average wind speed in September - Twin Peaks, CA
  • Average wind speed in September: 4.8mph

The windiest month (with the highest average wind speed) is April (6.6mph).
The calmest month (with the lowest average wind speed) is September (4.8mph).

Average humidity in September
Twin Peaks, CA

Average humidity in September - Twin Peaks, CA
  • Average humidity in September: 39%

The month with the highest relative humidity is February (52%).
The month with the lowest relative humidity is August (36%).

Average rainfall in September
Twin Peaks, CA

Average rainfall in September - Twin Peaks, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is December (1.42").
The driest month (with the least rainfall) is June (0.04").

Average rainfall days in September
Twin Peaks, CA

Average rainfall days in September - Twin Peaks, CA
  • Average rainfall days in September: 2.6 days

The month with the highest number of rainy days is March (7.3 days).
The month with the least rainy days is June (1.3 days).

Average snowfall days in September
Twin Peaks, CA

Average snowfall days in September - Twin Peaks, CA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

Average daylight in September /
Average sunshine in September
Twin Peaks, CA

Average daylight in September / Average sunshine in September - Twin Peaks, 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 month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 54min).

Average sunshine days in September
Twin Peaks, CA

Average sunshine days in September - Twin Peaks, CA
  • Average sunshine days in September: 25.7 days

The month with the most sunshine days is June (28.5 days).
The month with the least sunshine days is February (20.9 days).

Average UV index in September
Twin Peaks, CA

Average UV index in September - Twin Peaks, CA
  • Average UV index in September: 6

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

Average cloud cover in September
Twin Peaks, CA

Average cloud cover in September - Twin Peaks, 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
Twin Peaks, CA

Average visibility in September - Twin Peaks, 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).

Twin Peaks, California, USA

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