September weather forecast
Astoria, OR

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A scenic seaside shot of the city of Astoria in Oregon, with a view of the iconic Astoria Megler bridge crossing over the Columbia river
A scenic seaside shot of the city of Astoria in Oregon, with a view of the iconic Astoria Megler bridge crossing over the Columbia river

Weather in September

Astoria's weather in September marks the transition from the warm summer season to the cooler, wetter conditions of autumn. Foliage begins to change, landscapes adopt burnished hues, and a tangible shift in the city's ambience gains momentum. The temperature timeframe in September varies from 51.8°F (11°C) to 64.6°F (18.1°C), indicating a noticeable drop from the summer months. Moreover, September introduces an increasing propensity for rain, preparing for the rainy season starting October.

Temperature

Shifting into September, Astoria records an average high-temperature of a still enjoyable 64.6°F (18.1°C), presenting minor fluctuations compared to the previous month. The mean low-temperature during September nights in Astoria is a fresh 51.8°F (11°C).

Humidity

In Astoria, the average relative humidity in September is 83%.

Rainfall

In Astoria, Oregon, in September, during 12.4 rainfall days, 1.81" (46mm) of precipitation is typically accumulated. Throughout the year, in Astoria, there are 192.7 rainfall days, and 40.12" (1019mm) of precipitation is accumulated.

Snowfall

April through November are months without snowfall in Astoria.

Ocean temperature

In Astoria, in September, the average water temperature is 55.9°F (13.3°C).
Note: Swimming in 55.9°F (13.3°C) can be lethal. Merely spending a few minutes in 55.4°F (13°C) waters feels harsh, and venturing below 50°F (10°C) might disrupt breathing control and bring about cold shock, contingent on individual resilience.

Daylight

The average length of the day in September in Astoria, Oregon, is 12h and 31min.
On the first day of September in Astoria, Oregon, sunrise is at 6:36 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 6:56 pm PDT.

Sunshine

The average sunshine in September in Astoria is 8.7h.

UV index

In September, the average daily maximum UV index in Astoria is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: An average UV index of 4 in September transforms into this advice:
Undertake protective steps - Preventing sun damage is advised. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Protect your eyes, ears, face, and neck from the Sun by wearing a wide-brimmed hat.
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Frequently asked questions

What is the usual temperature for Astoria in September?

The high-temperature, in September, in Astoria, is 64.6°F (18.1°C), while the low-temperature averages to 51.8°F (11°C).

What is the average humidity in September in Astoria?

In Astoria, the average relative humidity in September is 83%.

How much does it rain in Astoria in September?

In September, in Astoria, the rain falls for 12.4 days. Throughout September, 1.81" (46mm) of precipitation is accumulated.

When it does not snow in Astoria?

In Astoria, Oregon, snow does not fall in April through November.

What is the ocean temperature in September in Astoria?

In Astoria, Oregon, in September, the average water temperature is 55.9°F (13.3°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

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

The average day length in September in Astoria, Oregon, is 12h and 31min.

When is the sunrise / sunset in September in Astoria?

On the first day of September in Astoria, Oregon, sunrise is at 6:36 am and sunset at 7:53 pm. On the last day of the month, sunrise is at 7:13 am and sunset at 6:56 pm PDT.

How long on average sun shines in September in Astoria?

The average sunshine duration in September is 8.7h.

What is the UV index intensity in September in Astoria?

The average daily maximum UV index in September in Astoria is 4. A UV Index of 3 to 5 symbolizes a medium health risk 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
Astoria, OR

Average temperature in September - Astoria, OR
  • Average high temperature in September: 64.6°F

The warmest month (with the highest average high temperature) is August (67.6°F).
The month with the lowest average high temperature is December (45.1°F).

  • Average low temperature in September: 51.8°F

The month with the highest average low temperature is August (53.1°F).
The coldest month (with the lowest average low temperature) is December (38.5°F).

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Average pressure in September
Astoria, OR

Average pressure in September - Astoria, OR
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.08"Hg).
The months with the lowest atmospheric pressure are March and September (30.02"Hg).

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Average wind speed in September
Astoria, OR

Average wind speed in September - Astoria, OR
  • Average wind speed in September: 6mph

The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).

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Average humidity in September
Astoria, OR

Average humidity in September - Astoria, OR
  • Average humidity in September: 83%

The months with the highest relative humidity are January, February, March, November and December (84%).
The month with the lowest relative humidity is May (81%).

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Average rainfall in September
Astoria, OR

Average rainfall in September - Astoria, OR
  • Average rainfall in September: 1.81"

The wettest month (with the highest rainfall) is December (6.42").
The driest month (with the least rainfall) is July (0.51").

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Average rainfall days in September
Astoria, OR

Average rainfall days in September - Astoria, OR
  • Average rainfall days in September: 12.4 days

The month with the highest number of rainy days is December (21.2 days).
The month with the least rainy days is August (7.2 days).

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Average snowfall in September
Astoria, OR

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

The month with the highest snowfall is February (0.91").
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
Astoria, OR

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

The month with the highest number of snowfall days is February (1.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average sea temperature in September
Astoria, OR

Average sea temperature in September - Astoria, OR
  • Average sea temperature in September: 55.9°F

The best month for swimming (with the highest average sea temperature) is July (56.9°F).
The coldest month (with the lowest average sea temperature) is February (47.7°F).

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

Average daylight in September / Average sunshine in September - Astoria, 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 4min

The month with the most sunshine is August (Average sunshine: 9h and 54min).
The months with the least sunshine are January and February (Average sunshine: 3h and 48min).

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Average sunshine days in September
Astoria, OR

Average sunshine days in September - Astoria, OR
  • Average sunshine days in September: 15.3 days

The month with the most sunshine days is August (20.1 days).
The month with the least sunshine days is February (7.5 days).

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Average UV index in September
Astoria, OR

Average UV index in September - Astoria, OR
  • 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).

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Average cloud cover in September
Astoria, OR

Average cloud cover in September - Astoria, OR
  • Average cloud cover in September: 38

The months with the most cloud cover are January and February (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 36).

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Average visibility in September
Astoria, OR

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

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

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Astoria, Oregon, USA

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