September weather forecast
Twin Falls, ID

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The high water of the Shoshone Falls in Twin Falls, Idaho, falling over the high rock cliffs and flowing into a river below
The high water of the Shoshone Falls in Twin Falls, Idaho, falling over the high rock cliffs and flowing into a river below

Weather in September

September brings with it the first hints of fall in Twin Falls. As compared to August, the temperature settles to a comforting 77.5°F (25.3°C) high, and the foliage begins to change color. The stark summer heat begins to diminish, and locals start experiencing cooler breezes. Outdoor activities pick up once again as people enjoy the gentle warmth of the sun without the intensity of the summer heat. As trees start to shed their leaves, Twin Falls prepares to bid goodbye to the summer season.

Temperature

The commencement of September indicates a shift in the average high-temperature, receding from August's hot 88°F (31.1°C) to a moderately hot 77.5°F (25.3°C). Twin Falls anticipates a considerable cooling off from the daytime high to an average minimum temperature of 54.5°F (12.5°C) in September.

Humidity

In Twin Falls, the average relative humidity in September is 34%.

Rainfall

In Twin Falls, in September, during 6.4 rainfall days, 0.35" (9mm) of precipitation is typically accumulated. In Twin Falls, during the entire year, the rain falls for 91.4 days and collects up to 9.29" (236mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

In Twin Falls, Idaho, the average length of the day in September is 12h and 28min.
On the first day of September, sunrise is at 7:03 am and sunset at 8:11 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 7:20 pm MDT.

Sunshine

In Twin Falls, the average sunshine in September is 9.5h.

UV index

In Twin Falls, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: A maximum high UV index of 5 in September translates into the following recommendations:
Undertake protective steps - Preventing sun damage is advised. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
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Frequently asked questions

What are September temperatures in Twin Falls?

The average high-temperature, in September, in Twin Falls, is 77.5°F (25.3°C), while the average low-temperature is 54.5°F (12.5°C).

What is the average humidity in September in Twin Falls?

In Twin Falls, Idaho, the average relative humidity in September is 34%.

How much does it rain in Twin Falls in September?

In Twin Falls, Idaho, in September, it is raining for 6.4 days, with typically 0.35" (9mm) of accumulated precipitation.

When it does not snow in Twin Falls?

May through September are months without snowfall in Twin Falls, Idaho.

Does it snow in Twin Falls in September?

In Twin Falls, Idaho, in September, it doesn't snow. In October, it regularly snows.

How many hours of daylight does Twin Falls have in September?

In September, the average day length in Twin Falls is 12h and 28min.

What time are sunrise and sunset in September in Twin Falls?

On the first day of September in Twin Falls, Idaho, sunrise is at 7:03 am and sunset at 8:11 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 7:20 pm MDT.

How long on average sun shines in September in Twin Falls?

In Twin Falls, the average sunshine duration in September is 9.5h.

How high is the UV index in September in Twin Falls?

In Twin Falls, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium hazard to health 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
Twin Falls, ID

Average temperature in September - Twin Falls, ID
  • Average high temperature in September: 77.5°F

The warmest month (with the highest average high temperature) is July (89.6°F).
The month with the lowest average high temperature is December (34°F).

  • Average low temperature in September: 54.5°F

The month with the highest average low temperature is July (62.1°F).
The coldest month (with the lowest average low temperature) is December (23°F).

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Average pressure in September
Twin Falls, ID

Average pressure in September - Twin Falls, ID
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is January (30.28"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).

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Average wind speed in September
Twin Falls, ID

Average wind speed in September - Twin Falls, ID
  • Average wind speed in September: 7.5mph

The windiest month (with the highest average wind speed) is April (10mph).
The calmest month (with the lowest average wind speed) is August (7.3mph).

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Average humidity in September
Twin Falls, ID

Average humidity in September - Twin Falls, ID
  • Average humidity in September: 34%

The month with the highest relative humidity is January (78%).
The month with the lowest relative humidity is July (28%).

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Average rainfall in September
Twin Falls, ID

Average rainfall in September - Twin Falls, ID
  • Average rainfall in September: 0.35"

The wettest month (with the highest rainfall) is December (1.3").
The driest months (with the least rainfall) are July and August (0.24").

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Average rainfall days in September
Twin Falls, ID

Average rainfall days in September - Twin Falls, ID
  • Average rainfall days in September: 6.4 days

The month with the highest number of rainy days is March (12.1 days).
The month with the least rainy days is August (4.4 days).

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Average snowfall in September
Twin Falls, ID

Average snowfall in September - Twin Falls, ID
  • Average snowfall in September: 0"

The month with the highest snowfall is January (5.04").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in September
Twin Falls, ID

Average snowfall days in September - Twin Falls, ID
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is December (9.4 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average daylight in September /
Average sunshine in September
Twin Falls, ID

Average daylight in September / Average sunshine in September - Twin Falls, ID
  • Average daylight in September: 12h and 3min

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).

  • Average sunshine in September: 9h and 3min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in September
Twin Falls, ID

Average sunshine days in September - Twin Falls, ID
  • Average sunshine days in September: 22.3 days

The month with the most sunshine days is August (23.3 days).
The month with the least sunshine days is March (14.7 days).

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Average UV index in September
Twin Falls, ID

Average UV index in September - Twin Falls, ID
  • Average UV index in September: 5

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
Twin Falls, ID

Average cloud cover in September - Twin Falls, ID
  • Average cloud cover in September: 14

The month with the most cloud cover is December (Cloud cover 40).
The months with the least cloud cover are July and August (Cloud cover 10).

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Average visibility in September
Twin Falls, ID

Average visibility in September - Twin Falls, ID
  • 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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Twin Falls, Idaho, USA

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