September weather forecast
Clinton, WA

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Weather in September

The first month of the autumn, September, is still a refreshing month in Clinton, Washington, with an average temperature fluctuating between 51.4°F (10.8°C) and 67.1°F (19.5°C).

Temperature

During the shift to September, a minor reduction in average high-temperature is observed, shifting from a pleasant 72.7°F (22.6°C) in August to a refreshing 67.1°F (19.5°C). Nighttime temperature experiences an average drop to a cool 51.4°F (10.8°C) in September.

Humidity

In Clinton, the average relative humidity in September is 77%.

Rainfall

In Clinton, during September, the rain falls for 11.3 days and regularly aggregates up to 1.5" (38mm) of precipitation. Throughout the year, there are 173.1 rainfall days, and 26.02" (661mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall.

Daylight

In September, the average length of the day is 12h and 33min.
On the first day of the month, sunrise is at 6:28 am and sunset at 7:49 pm. On the last day of September, sunrise is at 7:08 am and sunset at 6:49 pm PDT.

Sunshine

In September, the average sunshine is 9.4h.

UV index

In Clinton, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: In September, an average UV index of 4 transforms into the following instructions:
Heed the precautions - It is counselled to guard against solar damage. It's recommended to limit sun exposure when its radiation is at its peak during midday. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Updated: Jul 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

September temperatures vary between a high-temperature of 67.1°F (19.5°C) and a low-temperature of 51.4°F (10.8°C).

What is the average humidity in September?

In September, the average relative humidity is 77%.

How many days does it rain in September in Clinton?

In Clinton, in September, during 11.3 rainfall days, 1.5" (38mm) of precipitation is typically accumulated.

When it does not snow?

May through October are months without snowfall.

What is the average length of the day in September?

In September, the average day length is 12h and 33min.

What time are sunrise and sunset in September?

In September, on the first day of the month, sunrise is at 6:28 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:08 am and sunset at 6:49 pm PDT.

How long on average sun shines in September?

In Clinton, the average sunshine duration in September is 9.4h.

How high is the UV index in September?

In Clinton, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Clinton, WA

Average temperature in September - Clinton, WA
  • Average high temperature in September: 67.1°F

The warmest month (with the highest average high temperature) is August (72.7°F).
The month with the lowest average high temperature is December (42.6°F).

  • Average low temperature in September: 51.4°F

The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (35.4°F).

Average pressure in September
Clinton, WA

Average pressure in September - Clinton, WA
  • Average pressure in September: 30.01"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).

Average wind speed in September
Clinton, WA

Average wind speed in September - Clinton, WA
  • Average wind speed in September: 4.2mph

The windiest month (with the highest average wind speed) is November (6.2mph).
The calmest month (with the lowest average wind speed) is August (3.6mph).

Average humidity in September
Clinton, WA

Average humidity in September - Clinton, WA
  • Average humidity in September: 77%

The months with the highest relative humidity are February and December (84%).
The month with the lowest relative humidity is July (72%).

Average rainfall in September
Clinton, WA

Average rainfall in September - Clinton, WA
  • Average rainfall in September: 1.5"

The wettest month (with the highest rainfall) is December (3.54").
The driest month (with the least rainfall) is July (0.43").

Average rainfall days in September
Clinton, WA

Average rainfall days in September - Clinton, WA
  • Average rainfall days in September: 11.3 days

The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (6.3 days).

Average snowfall in September
Clinton, WA

Average snowfall in September - Clinton, WA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (4.61").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Clinton, WA

Average snowfall days in September - Clinton, WA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (5.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Clinton, WA

Average daylight in September / Average sunshine in September - Clinton, WA
  • Average daylight in September: 12h and 4min

The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in September: 9h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).

Average sunshine days in September
Clinton, WA

Average sunshine days in September - Clinton, WA
  • Average sunshine days in September: 16.5 days

The month with the most sunshine days is August (22.6 days).
The month with the least sunshine days is November (9.1 days).

Average UV index in September
Clinton, WA

Average UV index in September - Clinton, WA
  • Average UV index in September: 4

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Clinton, WA

Average cloud cover in September - Clinton, WA
  • Average cloud cover in September: 32

The month with the most cloud cover is December (Cloud cover 54).
The month with the least cloud cover is August (Cloud cover 25).

Average visibility in September
Clinton, WA

Average visibility in September - Clinton, WA
  • Average visibility in September: 6mi

The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).

Clinton, Washington, USA

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