September weather forecast
Rainier, OR

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Weather in September

September, the first month of the autumn in Rainier, is also an agreeable month, with an average temperature varying between 70.7°F (21.5°C) and 47.3°F (8.5°C).

Temperature

The onset of September brings a small shift in high-temperatures, falling from a warm 77.9°F (25.5°C) in August to a pleasant 70.7°F (21.5°C). Rainier, in September, experiences a marked contrast from daytime zeniths to a steady average low-temperature of 47.3°F (8.5°C).

Humidity

In September, the average relative humidity is 78%.

Rainfall

In Rainier, in September, it is raining for 10.8 days, with typically 1.26" (32mm) of accumulated precipitation. Throughout the year, in Rainier, there are 175.5 rainfall days, and 25.83" (656mm) of precipitation is accumulated.

Snowfall

In Rainier, snow does not fall in April through October.

Daylight

The average length of the day in September is 12h and 31min.
On the first day of September in Rainier, sunrise is at 6:33 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine is 8.4h.

UV index

In Rainier, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Rainier in September?

In September, in Rainier, the average high-temperature is 70.7°F (21.5°C), and the average low-temperature is 47.3°F (8.5°C).

What is the average humidity in September?

In Rainier, the average relative humidity in September is 78%.

How many days does it rain in September?

In Rainier, in September, during 10.8 rainfall days, 1.26" (32mm) of precipitation is typically accumulated.

When it does not snow?

In Rainier, snow does not fall in April through October.

What is the average length of the day in September?

In Rainier, the average day length in September is 12h and 31min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:33 am and sunset at 7:49 pm. On the last day of the month, in Rainier, sunrise is at 7:10 am and sunset at 6:52 pm PDT.

How long on average sun shines in September?

In Rainier, the average sunshine duration in September is 8.4h.

What is the UV index reading in September?

In Rainier, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
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
Rainier, OR

Average temperature in September - Rainier, OR
  • Average high temperature in September: 70.7°F

The warmest month (with the highest average high temperature) is August (77.9°F).
The month with the lowest average high temperature is December (42.3°F).

  • Average low temperature in September: 47.3°F

The month with the highest average low temperature is August (49.8°F).
The coldest month (with the lowest average low temperature) is December (32.7°F).

Average pressure in September
Rainier, OR

Average pressure in September - Rainier, OR
  • Average pressure in September: 30.01"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

Average wind speed in September
Rainier, OR

Average wind speed in September - Rainier, OR
  • Average wind speed in September: 3.9mph

The windiest month (with the highest average wind speed) is January (4.8mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).

Average humidity in September
Rainier, OR

Average humidity in September - Rainier, OR
  • Average humidity in September: 78%

The months with the highest relative humidity are January, February, November and December (88%).
The month with the lowest relative humidity is July (72%).

Average rainfall in September
Rainier, OR

Average rainfall in September - Rainier, OR
  • Average rainfall in September: 1.26"

The wettest month (with the highest rainfall) is January (3.9").
The driest month (with the least rainfall) is August (0.39").

Average rainfall days in September
Rainier, OR

Average rainfall days in September - Rainier, OR
  • Average rainfall days in September: 10.8 days

The month with the highest number of rainy days is March (20.3 days).
The month with the least rainy days is July (6.1 days).

Average snowfall in September
Rainier, OR

Average snowfall in September - Rainier, OR
  • Average snowfall in September: 0"

The month with the highest snowfall is January (1.26").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Rainier, OR

Average snowfall days in September - Rainier, OR
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (2.2 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in September /
Average sunshine in September
Rainier, OR

Average daylight in September / Average sunshine in September - Rainier, OR
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).

  • Average sunshine in September: 8h and 2min

The month with the most sunshine is August (Average sunshine: 10h and 24min).
The months with the least sunshine are January, February and December (Average sunshine: 3h and 30min).

Average sunshine days in September
Rainier, OR

Average sunshine days in September - Rainier, OR
  • Average sunshine days in September: 17 days

The month with the most sunshine days is July (22 days).
The month with the least sunshine days is March (8.9 days).

Average UV index in September
Rainier, OR

Average UV index in September - Rainier, OR
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 5).
The month with the lowest UV index is November (UV index 1).

Average cloud cover in September
Rainier, OR

Average cloud cover in September - Rainier, OR
  • Average cloud cover in September: 44

The months with the most cloud cover are February and March (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 36).

Average visibility in September
Rainier, OR

Average visibility in September - Rainier, OR
  • Average visibility in September: 4mi

The month with the highest visibility is August (5mi).
The months with the lowest visibility are January, February, March, April, May, June, July, September, October, November and December (4mi).

Rainier, Oregon, USA

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