September weather - Autumn 2024

Weather in September
Frequently asked questions
Average temperature in September
Average pressure in September
Average wind speed in September
Average humidity in September
Average rainfall in September
Average rainfall days in September
Average snowfall in September
Average snowfall days in September
Average daylight in September
Average sunshine in September
Average sunshine days in September
Average UV index in September
Average cloud cover in September
Average visibility in September

The small city of Walla Walla in Washington

Weather in September

September signifies the commencement of autumn, exhibiting a reduction in temperature from the summer months. Unwavering sunshine makes the transition from summer to fall smooth, creating days that are warm and nights that are comfortably cool. With trees beginning to change color, Walla display a vibrant autumnal color palette that gradually takes hold as the month progresses. Some areas may get an occasional shower, signaling the slow return of the rainy season. The weather softens to a high of 74.3°F (23.5°C), confirming September as the harbinger of autumn in Walla.

Temperature

The arrival of September corresponds with a temperature reduction, down from August's moderately hot 84.6°F (29.2°C) to a still warm 74.3°F (23.5°C). During the month of September, the nighttime temperature falls to an average of 53.6°F (12°C).

Humidity

In Walla, the average relative humidity in September is 47%.

Rainfall

In Walla, in September, it is raining for 7.6 days, with typically 0.55" (14mm) of accumulated precipitation. In Walla, Washington, during the entire year, the rain falls for 141.7 days and collects up to 15.12" (384mm) of precipitation.

Snowfall

Months with snowfall in Walla, Washington, are January through April, September, November and December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. Throughout the year, in Walla, Washington, there are 21.1 snowfall days, and 9.09" (231mm) of snow is accumulated.

Daylight

In Walla, the average length of the day in September is 12h and 31min.
On the first day of the month, sunrise is at 6:15 am and sunset at 7:31 pm. On the last day of September, sunrise is at 6:51 am and sunset at 6:34 pm PDT.

Sunshine

In September, the average sunshine is 10.5h.

UV index

The average daily maximum UV index in September in Walla is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In September, the maximum UV index of 4 suggests this advice:
Exercise care. People with light skin might get burns in fewer than 30 minutes. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. A wide-brimmed hat is a staple for defending the face, eyes, ears, and neck from the Sun. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.

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Frequently asked questions

What is the usual temperature for Walla in September?

The high-temperature during September is 74.3°F (23.5°C) and the low-temperature is 53.6°F (12°C). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which takes the relative humidity and factors it into the air temperature reading, in July is evaluated at 84.2°F (29°C).

What is the average humidity in September in Walla?

The average relative humidity in September in Walla is 47%.

How much does it rain in Walla in September?

In Walla, Washington, during September, the rain falls for 7.6 days and regularly aggregates up to 0.55" (14mm) of precipitation.

When does it start snowing in Walla?

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

How many hours of daylight does Walla have in September?

In September, the average day length is 12h and 31min.

When are sunrise and sunset in September in Walla?

On the first day of September, sunrise is at 6:15 am and sunset at 7:31 pm. On the last day of the month, sunrise is at 6:51 am and sunset at 6:34 pm PDT.

How many hours of sunshine does Walla have in September?

The average sunshine duration in September is 10.5h.

What is the UV index intensity in September in Walla?

The average daily maximum UV index in September in Walla, Washington, is 4. A UV Index of 3 to 5 symbolizes a medium health risk from unprotected exposure to 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

84.6°F 29.2°C

74.3°F 23.5°C

59.9°F 15.5°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

6.8mph 10.9km/h

6.2mph 10km/h

6.8mph 10.9km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

Average daylight

Average sunshine

Average sunshine days

21.8

20.1

17.4

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Walla Walla, WA

Average high temperature in September: 74.3°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is December (37.4°F).

Average low temperature in September: 53.6°F

The month with the highest average low temperature is August (60.8°F).
The coldest month (with the lowest average low temperature) is December (27°F).

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Average pressure in September
Walla Walla, WA

Average pressure in September: 29.95"Hg

The month with the highest atmospheric pressure is January (30.2"Hg).
The month with the lowest atmospheric pressure is August (29.9"Hg).

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Average wind speed in September
Walla Walla, WA

Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is April (7.9mph).
The calmest month (with the lowest average wind speed) is September (5.9mph).

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Average humidity in September
Walla Walla, WA

Average humidity in September: 47%

The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is August (39%).

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Average rainfall in September
Walla Walla, WA

Average rainfall in September: 0.55"

The wettest month (with the highest rainfall) is March (2.01").
The driest month (with the least rainfall) is July (0.35").

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Average rainfall days in September
Walla Walla, WA

Average rainfall days in September: 7.6 days

The month with the highest number of rainy days is March (17.4 days).
The month with the least rainy days is July (4.9 days).

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Average snowfall in September
Walla Walla, WA

Average snowfall in September: 0.08"

The month with the highest snowfall is February (2.91").
The months with the least snowfall are May, June, July, August and October (0").

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Average snowfall days in September
Walla Walla, WA

Average snowfall days in September: 0.1 days

The months with the highest number of snowfall days are February and December (6.1 days).
The months with the least snowfall days are May, June, July and August (0 days).

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

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: 10h and 3min

The month with the most sunshine is August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 18min).

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Average sunshine days in September
Walla Walla, WA

Average sunshine days in September: 20.1 days

The month with the most sunshine days is July (24.4 days).
The month with the least sunshine days is February (10 days).

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Average UV index in September
Walla Walla, WA

Average UV index in September: 4

The month with the highest UV index is July (UV index 7).
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
Walla Walla, WA

Average cloud cover in September: 17

The months with the most cloud cover are January, February and December (Cloud cover 44).
The months with the least cloud cover are July and August (Cloud cover 10).

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Average visibility in September
Walla Walla, 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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September weather forecast
Walla Walla, WA

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