September weather forecast
Sequim, WA

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A vast lavender farm with fully blossomed purple flowers in rows, in Sequin, Washington
A vast lavender farm with fully blossomed purple flowers in rows, in Sequin, Washington

Weather in September

September signals the end of the peak summer period and welcomes the arrival of Fall in Sequim. With the average high temperature decreasing to 62.6°F (17°C), there's a slight nip in the air. September usually experiences a spell of late summer with clear skies and lower humidity. The change in season affects the color of trees, with leaves turning into shades of yellow, orange, and red. The nature trails in and around Sequim are a visual treat during this month.

Temperature

September marks a gentle change in average high-temperature, declining from August's pleasant 68°F (20°C) to an enjoyable 62.6°F (17°C). An average nighttime temperature of 49.3°F (9.6°C) is recorded during September.

Humidity

The average relative humidity in September in Sequim is 79%.

Rainfall

In Sequim, during September, the rain falls for 12.9 days and regularly aggregates up to 1.54" (39mm) of precipitation. Throughout the year, in Sequim, there are 174.1 rainfall days, and 19.45" (494mm) of precipitation is accumulated.

Snowfall

May through October are months without snowfall.

Daylight

In Sequim, Washington, the average length of the day in September is 12h and 33min.
On the first day of the month, sunrise is at 6:31 am and sunset at 7:52 pm. On the last day of September, in Sequim, sunrise is at 7:11 am and sunset at 6:52 pm PDT.

Sunshine

In September, the average sunshine is 9.4h.

UV index

May through September, with an average maximum UV index of 4, are months with the highest UV index in Sequim. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index, 4 during September, leads to the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Updated: Feb 14, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Sequim in September?

The high-temperature in Sequim, Washington, during September is 62.6°F (17°C) and the low-temperature is 49.3°F (9.6°C).

What is the average humidity in September in Sequim?

In September, the average relative humidity in Sequim, Washington, is 79%.

How many days does it rain in September in Sequim?

In September, in Sequim, the rain falls for 12.9 days. Throughout September, 1.54" (39mm) of precipitation is accumulated.

When it does not snow in Sequim?

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

How many hours of daylight does Sequim have in September?

In Sequim, the average day length in September is 12h and 33min.

When is the sunrise / sunset in September in Sequim?

On the first day of September in Sequim, Washington, sunrise is at 6:31 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 6:52 pm PDT.

How long on average sun shines in September in Sequim?

In Sequim, the average sunshine duration in September is 9.4h.

What is the month with the highest UV index in Sequim?

May through September, with an average maximum UV index of 4, are months with the highest UV index in Sequim, Washington.

What is the UV index reading in September in Sequim?

In Sequim, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health risk from unsafe 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
Sequim, WA

Average temperature in September - Sequim, WA
  • Average high temperature in September: 62.6°F

The warmest month (with the highest average high temperature) is August (68°F).
The month with the lowest average high temperature is December (41.2°F).

  • Average low temperature in September: 49.3°F

The month with the highest average low temperature is August (52.3°F).
The coldest month (with the lowest average low temperature) is February (34.3°F).

Average pressure in September
Sequim, WA

Average pressure in September - Sequim, WA
  • Average pressure in September: 30.02"Hg

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

Average wind speed in September
Sequim, WA

Average wind speed in September - Sequim, WA
  • Average wind speed in September: 3.7mph

The windiest month (with the highest average wind speed) is November (5.9mph).
The calmest months (with the lowest average wind speed) are August and September (3.7mph).

Average humidity in September
Sequim, WA

Average humidity in September - Sequim, WA
  • Average humidity in September: 79%

The months with the highest relative humidity are January and February (85%).
The months with the lowest relative humidity are July and August (75%).

Average rainfall in September
Sequim, WA

Average rainfall in September - Sequim, WA
  • Average rainfall in September: 1.54"

The wettest month (with the highest rainfall) is January (2.56").
The driest month (with the least rainfall) is July (0.59").

Average rainfall days in September
Sequim, WA

Average rainfall days in September - Sequim, WA
  • Average rainfall days in September: 12.9 days

The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (6.8 days).

Average snowfall in September
Sequim, WA

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

The month with the highest snowfall is February (2.17").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in September
Sequim, WA

Average snowfall days in September - Sequim, 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 daylight in September /
Average sunshine in September
Sequim, WA

Average daylight in September / Average sunshine in September - Sequim, 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 2min

The month with the most sunshine is August (Average sunshine: 11h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).

Average sunshine days in September
Sequim, WA

Average sunshine days in September - Sequim, WA
  • Average sunshine days in September: 14.8 days

The month with the most sunshine days is August (21.4 days).
The month with the least sunshine days is March (8.9 days).

Average UV index in September
Sequim, WA

Average UV index in September - Sequim, WA
  • Average UV index in September: 4

The months with the highest UV index are May, June, July, August and September (UV index 4).
The months with the lowest UV index are January, February, March, November and December (UV index 2).

Average cloud cover in September
Sequim, WA

Average cloud cover in September - Sequim, WA
  • Average cloud cover in September: 30

The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 21).

Average visibility in September
Sequim, WA

Average visibility in September - Sequim, 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).

Sequim, Washington, USA

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