September weather forecast
Monmouth, OR

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Weather in September

The first month of the autumn, September, is still a warm month in Monmouth, Oregon, with an average temperature varying between 73.8°F (23.2°C) and 50°F (10°C).

Temperature

The arrival of September correlates with a minor temperature reduction, down from August's warm 80.8°F (27.1°C) to a still moderately hot 73.8°F (23.2°C). September presents a sharp fall from Monmouth's daytime highs to an average low-temperature of 50°F (10°C).

Humidity

The average relative humidity in September in Monmouth is 73%.

Rainfall

In Monmouth, during September, the rain falls for 7.8 days and regularly aggregates up to 0.43" (11mm) of precipitation. In Monmouth, during the entire year, the rain falls for 144.6 days and collects up to 10.04" (255mm) of precipitation.

Snowfall

In Monmouth, snow does not fall in April through November.

Daylight

In Monmouth, the average length of the day in September is 12h and 30min.
On the first day of the month, sunrise is at 6:36 am and sunset at 7:49 pm. On the last day of September, in Monmouth, sunrise is at 7:10 am and sunset at 6:54 pm PDT.

Sunshine

In Monmouth, Oregon, the average sunshine in September is 9.2h.

UV index

The average daily maximum UV index in September in Monmouth is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: A typical high UV index of 4 in September suggests the following recommendations:
Be vigilant - A duty to shield skin and eyes from injury exists. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
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Frequently asked questions

What is the usual temperature for Monmouth in September?

The average high-temperature, in September, in Monmouth, is 73.8°F (23.2°C), while the average low-temperature is 50°F (10°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which combines air temperature and relative humidity, in August is computed to be 84.2°F (29°C).

What is the average humidity in September in Monmouth?

The average relative humidity in September in Monmouth, Oregon, is 73%.

How much does it rain in Monmouth in September?

In Monmouth, Oregon, in September, during 7.8 rainfall days, 0.43" (11mm) of precipitation is typically accumulated.

When it does not snow in Monmouth?

April through November are months without snowfall.

What is the average length of the day in September in Monmouth?

The average day length in September in Monmouth, Oregon, is 12h and 30min.

What time are sunrise and sunset in September in Monmouth?

On the first day of September, sunrise is at 6:36 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:54 pm PDT.

How long on average sun shines in September in Monmouth?

In Monmouth, Oregon, the average sunshine duration in September is 9.2h.

What is the UV index reading in September in Monmouth?

In September, the average daily maximum UV index is 4. A UV Index estimate of 3 to 5 represents a moderate health threat 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
Monmouth, OR

Average temperature in September - Monmouth, OR
  • Average high temperature in September: 73.8°F

The warmest month (with the highest average high temperature) is August (80.8°F).
The month with the lowest average high temperature is December (44.2°F).

  • Average low temperature in September: 50°F

The month with the highest average low temperature is August (52.5°F).
The coldest month (with the lowest average low temperature) is December (34.2°F).

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Average pressure in September
Monmouth, OR

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

The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).

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Average wind speed in September
Monmouth, OR

Average wind speed in September - Monmouth, OR
  • Average wind speed in September: 4mph

The windiest month (with the highest average wind speed) is March (5.1mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

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Average humidity in September
Monmouth, OR

Average humidity in September - Monmouth, OR
  • Average humidity in September: 73%

The months with the highest relative humidity are February and December (88%).
The month with the lowest relative humidity is August (68%).

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Average rainfall in September
Monmouth, OR

Average rainfall in September - Monmouth, OR
  • Average rainfall in September: 0.43"

The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is July (0.12").

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Average rainfall days in September
Monmouth, OR

Average rainfall days in September - Monmouth, OR
  • Average rainfall days in September: 7.8 days

The month with the highest number of rainy days is March (17.8 days).
The month with the least rainy days is August (4 days).

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Average snowfall in September
Monmouth, OR

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

The month with the highest snowfall is February (0.55").
The months with the least snowfall are April, May, June, July, August, September, October and November (0").

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Average snowfall days in September
Monmouth, OR

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

The month with the highest number of snowfall days is February (1.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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

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

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in September: 9h and 1min

The months with the most sunshine are July and August (Average sunshine: 10h and 54min).
The month with the least sunshine is February (Average sunshine: 4h and 0min).

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Average sunshine days in September
Monmouth, OR

Average sunshine days in September - Monmouth, OR
  • Average sunshine days in September: 19.1 days

The month with the most sunshine days is July (24.9 days).
The month with the least sunshine days is March (9.7 days).

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Average UV index in September
Monmouth, OR

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

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

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Average cloud cover in September
Monmouth, OR

Average cloud cover in September - Monmouth, OR
  • Average cloud cover in September: 33

The months with the most cloud cover are February and March (Cloud cover 61).
The month with the least cloud cover is August (Cloud cover 23).

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Average visibility in September
Monmouth, OR

Average visibility in September - Monmouth, OR
  • Average visibility in September: 5mi

The month with the highest visibility is August (6mi).
The months with the lowest visibility are January, February, March, April, November and December (4mi).

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Monmouth, Oregon, USA

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