September weather forecast
Oso, WA

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Weather in September

The first month of the autumn, September, is also an enjoyable month in Oso, Washington, with an average temperature fluctuating between 66.2°F (19°C) and 49.1°F (9.5°C).

Temperature

The onset of September results in a small decrease in the average high-temperature, moderately receding from a pleasant 72.3°F (22.4°C) in August to a refreshing 66.2°F (19°C). Oso in September anticipates an average nighttime temperature of 49.1°F (9.5°C).

Humidity

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

Rainfall

In Oso, Washington, during September, the rain falls for 13.5 days and regularly aggregates up to 2.05" (52mm) of precipitation. Throughout the year, in Oso, Washington, there are 188.6 rainfall days, and 34.92" (887mm) of precipitation is accumulated.

Snowfall

In Oso, snow does not fall in May through October.

Daylight

In Oso, the average length of the day in September is 12h and 34min.
On the first day of the month, sunrise is at 6:26 am and sunset at 7:48 pm. On the last day of September, sunrise is at 7:06 am and sunset at 6:48 pm PDT.

Sunshine

In Oso, the average sunshine in September is 9.2h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.
Note: In September, an average UV index of 4 transforms into the following instructions:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.

Frequently asked questions

What are the temperatures in Oso in September?

During September, Oso experiences an average high-temperature of 66.2°F (19°C) and a low-temperature of 49.1°F (9.5°C).

What is the average humidity in September in Oso?

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

How many days does it rain in September in Oso?

In Oso, in September, it is raining for 13.5 days, with typically 2.05" (52mm) of accumulated precipitation.

When it does not snow in Oso?

May through October are months without snowfall.

How many hours of daylight does Oso have in September?

In Oso, Washington, the average day length in September is 12h and 34min.

When are sunrise and sunset in September in Oso?

In September, on the first day of the month, sunrise is at 6:26 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 6:48 pm PDT.

How long on average sun shines in September in Oso?

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

How high is the UV index in September in Oso?

The average daily maximum UV index in September is 4. A UV Index estimate 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
Oso, WA

Average temperature in September - Oso, WA
  • Average high temperature in September: 66.2°F

The warmest month (with the highest average high temperature) is August (72.3°F).
The month with the lowest average high temperature is December (41.7°F).

  • Average low temperature in September: 49.1°F

The month with the highest average low temperature is August (51.6°F).
The coldest month (with the lowest average low temperature) is February (33.8°F).

Average pressure in September
Oso, WA

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

The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).

Average wind speed in September
Oso, WA

Average wind speed in September - Oso, WA
  • Average wind speed in September: 3.9mph

The windiest months (with the highest average wind speed) are January and November (5.6mph).
The calmest month (with the lowest average wind speed) is August (3.3mph).

Average humidity in September
Oso, WA

Average humidity in September - Oso, WA
  • Average humidity in September: 78%

The months with the highest relative humidity are January, February, November and December (85%).
The month with the lowest relative humidity is July (73%).

Average rainfall in September
Oso, WA

Average rainfall in September - Oso, WA
  • Average rainfall in September: 2.05"

The wettest month (with the highest rainfall) is November (4.92").
The driest month (with the least rainfall) is July (0.51").

Average rainfall days in September
Oso, WA

Average rainfall days in September - Oso, WA
  • Average rainfall days in September: 13.5 days

The month with the highest number of rainy days is March (20.9 days).
The month with the least rainy days is August (6.9 days).

Average snowfall in September
Oso, WA

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

The month with the highest snowfall is February (4.45").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Oso, WA

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

The month with the highest number of snowfall days is February (4.3 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
Oso, WA

Average daylight in September / Average sunshine in September - Oso, 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 24min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).

Average sunshine days in September
Oso, WA

Average sunshine days in September - Oso, WA
  • Average sunshine days in September: 15.2 days

The month with the most sunshine days is August (22 days).
The month with the least sunshine days is March (8.1 days).

Average UV index in September
Oso, WA

Average UV index in September - Oso, 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, October, November and December (UV index 2).

Average cloud cover in September
Oso, WA

Average cloud cover in September - Oso, WA
  • Average cloud cover in September: 34

The month with the most cloud cover is December (Cloud cover 57).
The months with the least cloud cover are July and August (Cloud cover 26).

Average visibility in September
Oso, WA

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

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

Oso, Washington, USA

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