September weather forecast
Twisp, WA

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Weather in September

September in Twisp, Washington represents a shift in seasons, from warm summer to cooler fall, reflecting a pleasant mix of lingering summer warmth and incoming autumnal chill. Following the peak of summer temperatures in August, September offers a relief with a significant drop in average maximum temperature to 65.3°F (18.5°C). Twilight hours witness the setting in of mild chill, a telltale sign of the approaching fall. This is an ideal time for sightseeing around the city, without the summer heat or winter cold hampering the experience. September, with its beckoning autumnal colors and gentle weather, introduces a serene tempo to city life.

Temperature

September in Twisp comes with a decrease in the average high-temperature, falling from a warm 76.8°F (24.9°C) in August to a refreshing 65.3°F (18.5°C). Twisp sees a consistent average low-temperature of 42.1°F (5.6°C) in September, indicating a substantial decrease from the day's temperature.

Humidity

In Twisp, the average relative humidity in September is 60%.

Rainfall

In Twisp, during September, the rain falls for 9.8 days and regularly aggregates up to 0.94" (24mm) of precipitation. Throughout the year, in Twisp, there are 141.4 rainfall days, and 18.07" (459mm) of precipitation is accumulated.

Snowfall

Months with snowfall in Twisp are January through April, September through December. September is the first month it typically snows in Twisp, Washington. Throughout September, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. In Twisp, during the entire year, snow falls for 64.4 days and aggregates up to 42.6" (1082mm) of snow.

Daylight

In September, the average length of the day in Twisp is 12h and 34min.
On the first day of September in Twisp, sunrise is at 6:19 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:40 pm PDT.

Sunshine

In September, the average sunshine in Twisp is 10.7h.

UV index

In September, the average daily maximum UV index in Twisp, Washington, is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily high UV index of 3 during September translates into the following recommendations:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. It's recommended to limit sun exposure when its radiation is at its peak during midday. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
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Frequently asked questions

What is the average September temperature in Twisp?

The high-temperature, in September, in Twisp, records 65.3°F (18.5°C), while the low-temperature is 42.1°F (5.6°C).

What is the average humidity in September in Twisp?

In Twisp, the average relative humidity in September is 60%.

How much does it rain in Twisp in September?

In Twisp, Washington, in September, it is raining for 9.8 days, with typically 0.94" (24mm) of accumulated precipitation.

When does it start to snow in Twisp?

September is the first month it typically snows in Twisp, Washington. Throughout September, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow.

How many hours of daylight does Twisp have in September?

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

When is the sunrise / sunset in September in Twisp?

In September, on the first day of the month, sunrise is at 6:19 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:40 pm PDT.

How many hours of sunshine does Twisp have in September?

In Twisp, the average sunshine duration in September is 10.7h.

How high is the UV index in September in Twisp?

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

Average temperature in September - Twisp, WA
  • Average high temperature in September: 65.3°F

The warmest month (with the highest average high temperature) is August (76.8°F).
The month with the lowest average high temperature is December (27.9°F).

  • Average low temperature in September: 42.1°F

The month with the highest average low temperature is August (48.9°F).
The coldest month (with the lowest average low temperature) is December (14.7°F).

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Average pressure in September
Twisp, WA

Average pressure in September - Twisp, WA
  • Average pressure in September: 29.98"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is August (29.94"Hg).

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Average wind speed in September
Twisp, WA

Average wind speed in September - Twisp, WA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is July (5.1mph).
The calmest months (with the lowest average wind speed) are January and December (3.5mph).

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Average humidity in September
Twisp, WA

Average humidity in September - Twisp, WA
  • Average humidity in September: 60%

The months with the highest relative humidity are January and February (92%).
The months with the lowest relative humidity are July and August (51%).

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Average rainfall in September
Twisp, WA

Average rainfall in September - Twisp, WA
  • Average rainfall in September: 0.94"

The wettest month (with the highest rainfall) is December (2.52").
The driest month (with the least rainfall) is July (0.35").

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Average rainfall days in September
Twisp, WA

Average rainfall days in September - Twisp, WA
  • Average rainfall days in September: 9.8 days

The month with the highest number of rainy days is March (17.1 days).
The month with the least rainy days is August (5.7 days).

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Average snowfall in September
Twisp, WA

Average snowfall in September - Twisp, WA
  • Average snowfall in September: 0.08"

The month with the highest snowfall is December (12.28").
The months with the least snowfall are May, June, July and August (0").

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Average snowfall days in September
Twisp, WA

Average snowfall days in September - Twisp, WA
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (15.5 days).
The months with the least snowfall days are June, July and August (0 days).

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

Average daylight in September / Average sunshine in September - Twisp, 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: 10h and 4min

The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).

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Average sunshine days in September
Twisp, WA

Average sunshine days in September - Twisp, WA
  • Average sunshine days in September: 17.6 days

The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is March (8.9 days).

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Average UV index in September
Twisp, WA

Average UV index in September - Twisp, WA
  • Average UV index in September: 3

The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February and November (UV index 1).

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Average cloud cover in September
Twisp, WA

Average cloud cover in September - Twisp, WA
  • Average cloud cover in September: 22

The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 14).

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Average visibility in September
Twisp, WA

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

The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The month with the lowest visibility is January (3mi).

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Twisp, Washington, USA

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