September weather forecast
Birch Bay, WA

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Weather in September

The first month of the autumn, September, is still a refreshing month in Birch Bay, Washington, with an average temperature fluctuating between 52°F (11.1°C) and 64.8°F (18.2°C).

Temperature

Birch Bay records an average high-temperature of an enjoyable 64.8°F (18.2°C) in September, closely mirroring the climate of the previous month. The average temperature during September nights in Birch Bay is registered at a fresh 52°F (11.1°C).

Humidity

In September, the average relative humidity is 79%.

Rainfall

In Birch Bay, during September, the rain falls for 12.8 days and regularly aggregates up to 2.36" (60mm) of precipitation. Throughout the year, there are 176.1 rainfall days, and 43.78" (1112mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall in Birch Bay, Washington.

Ocean temperature

In Birch Bay, the average seawater temperature in September is 52.5°F (11.4°C).
Note: Swimming in 52.5°F (11.4°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.

Daylight

In Birch Bay, the average length of the day in September is 12h and 34min.
On the first day of September in Birch Bay, Washington, sunrise is at 6:28 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:50 pm PDT.

Sunshine

The average sunshine in September is 8.9h.

UV index

The average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: The daily high UV index of 3 during September translates into the following recommendations:
Take necessary precautions - Defending against sun damage is advocated. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
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Frequently asked questions

What is the temperature in September in Birch Bay?

September temperatures vary between a high-temperature of 64.8°F (18.2°C) and a low-temperature of 52°F (11.1°C).

What is the average humidity in September in Birch Bay?

The average relative humidity in September in Birch Bay, Washington, is 79%.

How many days does it rain in September in Birch Bay?

In September, the rain falls for 12.8 days. Throughout September, 2.36" (60mm) of precipitation is accumulated.

When it does not snow in Birch Bay?

In Birch Bay, snow does not fall in May through October.

What is the water temperature in September in Birch Bay?

In Birch Bay, Washington, the average seawater temperature in September is 52.5°F (11.4°C). Swimming in 52.5°F (11.4°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

How many hours of daylight does Birch Bay have in September?

In September, the average day length in Birch Bay is 12h and 34min.

When is the sunrise / sunset in September in Birch Bay?

In September, on the first day of the month, sunrise is at 6:28 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:50 pm PDT.

How many hours of sunshine does Birch Bay have in September?

In Birch Bay, the average sunshine duration in September is 8.9h.

How high is the UV index in September in Birch Bay?

In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium hazard to health 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
Birch Bay, WA

Average temperature in September - Birch Bay, WA
  • Average high temperature in September: 64.8°F

The warmest month (with the highest average high temperature) is August (70°F).
The month with the lowest average high temperature is December (41.9°F).

  • Average low temperature in September: 52°F

The month with the highest average low temperature is August (54.9°F).
The coldest month (with the lowest average low temperature) is February (35.8°F).

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Average pressure in September
Birch Bay, WA

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

The month with the highest atmospheric pressure is January (30.07"Hg).
The month with the lowest atmospheric pressure is March (30"Hg).

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Average wind speed in September
Birch Bay, WA

Average wind speed in September - Birch Bay, WA
  • Average wind speed in September: 4.3mph

The windiest months (with the highest average wind speed) are November and December (6.3mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).

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Average humidity in September
Birch Bay, WA

Average humidity in September - Birch Bay, WA
  • Average humidity in September: 79%

The months with the highest relative humidity are January and November (83%).
The month with the lowest relative humidity is July (74%).

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Average rainfall in September
Birch Bay, WA

Average rainfall in September - Birch Bay, WA
  • Average rainfall in September: 2.36"

The wettest month (with the highest rainfall) is November (7.13").
The driest month (with the least rainfall) is July (0.67").

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Average rainfall days in September
Birch Bay, WA

Average rainfall days in September - Birch Bay, WA
  • Average rainfall days in September: 12.8 days

The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (6.1 days).

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Average snowfall in September
Birch Bay, WA

Average snowfall in September - Birch Bay, WA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.05").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in September
Birch Bay, WA

Average snowfall days in September - Birch Bay, WA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (3.7 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average sea temperature in September
Birch Bay, WA

Average sea temperature in September - Birch Bay, WA
  • Average sea temperature in September: 52.6°F

The best months for swimming (with the highest average sea temperature) are August and September (52.6°F).
The coldest month (with the lowest average sea temperature) is February (44.5°F).

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Average daylight in September /
Average sunshine in September
Birch Bay, WA

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

The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).

  • Average sunshine in September: 8h and 5min

The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The months with the least sunshine are January and December (Average sunshine: 3h and 54min).

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Average sunshine days in September
Birch Bay, WA

Average sunshine days in September - Birch Bay, WA
  • Average sunshine days in September: 15.6 days

The month with the most sunshine days is August (23.2 days).
The month with the least sunshine days is November (8.8 days).

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Average UV index in September
Birch Bay, WA

Average UV index in September - Birch Bay, WA
  • Average UV index in September: 3

The months with the highest UV index are June and 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
Birch Bay, WA

Average cloud cover in September - Birch Bay, WA
  • Average cloud cover in September: 35

The months with the most cloud cover are January and December (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 26).

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Average visibility in September
Birch Bay, WA

Average visibility in September - Birch Bay, WA
  • Average visibility in September: 6mi

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

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Birch Bay, Washington, USA

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