September weather forecastBremerton, WA

September

Weather in September

September ushers in mild autumnal charm in Bremerton, with gradually decreasing temperatures and shortening daylight hours. Rainfall accelerates during September, hitting a notable uptick of 0.59" (15mm) from the previous month. The reduced use of UV protection marks the declining sun intensity. The beautiful scenery of changing foliage and changing weather patterns sets the tone for the cooler months ahead.

Temperature

During the shift to September, Bremerton records a mild decrease in average high-temperature, moving from a moderately hot 77.2°F (25.1°C) in August to a pleasant 70°F (21.1°C). During September, Bremerton experiences an average low-temperature of 50.9°F (10.5°C) at night.

Humidity

In Bremerton, Washington, the average relative humidity in September is 75%.

Rainfall

In Bremerton, in September, during 9.9 rainfall days, 0.59" (15mm) of precipitation is typically accumulated. Throughout the year, there are 138.9 rainfall days, and 12.24" (311mm) of precipitation is accumulated.

Snowfall

In Bremerton, Washington, snow does not fall in April through October.

Ocean temperature

August and September, with an average ocean temperature of 53.2°F (11.8°C), are months with the warmest seawater.
Note: It is advised against swimming in 53.2°F (11.8°C) when it drops below 50°F (10°C). Such temperatures can cause extreme cold shock, leading to hyperventilation.

Daylight

In September, the average length of the day is 12h and 33min.
On the first day of the month, sunrise is at 6:30 am and sunset at 7:50 pm. On the last day of September, in Bremerton, sunrise is at 7:09 am and sunset at 6:51 pm PDT.

Sunshine

The average sunshine in September in Bremerton is 9.3h.

UV index

In September, the average daily maximum UV index in Bremerton is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: In September, a daily UV index of 4 turns into the following recommendations:
Ensure safety - Imperative it is to shield skin and eyes from damage. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Boost your sun resistance with garments that are densely woven yet spacious.

Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

The average high-temperature and low-temperature during September are 70°F (21.1°C) and 50.9°F (10.5°C) respectively.

In Bremerton, Washington, the average relative humidity in September is 75%.

In September, the rain falls for 9.9 days. Throughout September, 0.59" (15mm) of precipitation is accumulated.

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

August and September, with an average ocean temperature of 53.2°F (11.8°C), are months with the warmest seawater.

In Bremerton, Washington, in September, the average water temperature is 53.2°F (11.8°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.

The average day length in September in Bremerton, Washington, is 12h and 33min.

In September, on the first day of the month, sunrise is at 6:30 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:51 pm PDT.

The average sunshine duration in September is 9.3h.

The average daily maximum UV index in September in Bremerton is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to the Sun's UV radiation.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

77.2°F

70°F

58.6°F

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

4mph

4.3mph

5.1mph

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

5.4

9.9

11.8

Average snowfall

Average snowfall days

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

22.8

18.5

16.6

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Bremerton, WA

Average high temperature in September: 70°F

The warmest month (with the highest average high temperature) is August (77.2°F).
The month with the lowest average high temperature is December (43.2°F).

Average low temperature in September: 50.9°F

The month with the highest average low temperature is August (53.6°F).
The coldest month (with the lowest average low temperature) is December (34.9°F).

Average pressure in September
Bremerton, WA

Average pressure in September: 30.01"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).

Average wind speed in September
Bremerton, WA

Average wind speed in September: 4.1mph

The windiest month (with the highest average wind speed) is March (5.5mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).

Average humidity in September
Bremerton, WA

Average humidity in September: 75%

The month with the highest relative humidity is December (87%).
The month with the lowest relative humidity is July (69%).

Average rainfall in September
Bremerton, WA

Average rainfall in September: 0.59"

The wettest months (with the highest rainfall) are January and December (2.05").
The driest month (with the least rainfall) is July (0.28").

Average rainfall days in September
Bremerton, WA

Average rainfall days in September: 9.9 days

The month with the highest number of rainy days is March (15.3 days).
The month with the least rainy days is August (5.4 days).

Average snowfall in September
Bremerton, WA

Average snowfall in September: 0"

The month with the highest snowfall is February (1.22").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in September
Bremerton, WA

Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (2.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in September
Bremerton, WA

Average sea temperature in September: 53.1°F

The best month for swimming (with the highest average sea temperature) is August (53.2°F).
The coldest month (with the lowest average sea temperature) is February (45.3°F).

Average daylight in September /
Average sunshine in September
Bremerton, WA

Average daylight in September: 12h and 30min

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

Average sunshine in September: 9h and 18min

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
Bremerton, WA

Average sunshine days in September: 18.5 days

The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is February (11.8 days).

Average UV index in September
Bremerton, WA

Average UV index in September: 4

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Bremerton, WA

Average cloud cover in September: 34

The month with the most cloud cover is December (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 25).

Average visibility in September
Bremerton, WA

Average visibility in September: 6mi

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