September weather forecast
Stanley, ID

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A mirror image of the iconic Sawtooth Mountain Range located in Meadow Creek in Stanley, Idaho, in the famed Sawtooth National Recreation Area
A mirror image of the iconic Sawtooth Mountain Range located in Meadow Creek in Stanley, Idaho, in the famed Sawtooth National Recreation Area

Weather in September

September signifies the commencement of fall in Stanley. The landscape begins to shift its colours as temperatures start to decline, averaging 62.1°F (16.7°C) in the daytime. An increase in rainfall from the summer months rehydrates the environment preparing it for the upcoming cold months. Residents and visitors alike revel in the changing seasons, watching as the surroundings transition from vibrant summer greens to the orange hues of fall.

Temperature

The transition into September involves a decrease in the average high-temperature, falling from a pleasant 71.4°F (21.9°C) in August to a comfortable 62.1°F (16.7°C). Stanley experiences a substantial divergence from daytime highs in September, with average lows hovering around an icy 36.5°F (2.5°C).

Humidity

The average relative humidity in September is 53%.

Rainfall

In Stanley, in September, it is raining for 9.5 days, with typically 1.18" (30mm) of accumulated precipitation. Throughout the year, there are 98.2 rainfall days, and 19.25" (489mm) of precipitation is accumulated.

Snowfall

January through June, September through December are months with snowfall in Stanley. September is the first month it typically snows in Stanley. Throughout September, in the average 1.5 snowfall days, it receives 1.38" (35mm) of snow. In Stanley, during the entire year, snow falls for 131.3 days and aggregates up to 100.24" (2546mm) of snow.

Daylight

The average length of the day in September is 12h and 29min.
On the first day of the month, sunrise is at 7:03 am and sunset at 8:15 pm. On the last day of September, sunrise is at 7:37 am and sunset at 7:21 pm MDT.

Sunshine

In Stanley, the average sunshine in September is 9h.

UV index

The average daily maximum UV index in September is 2. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index, 2 in September, converts into the following recommendations:
Many can withstand an hour in the sun without burning, yet children must always have protection against sunlight. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Watch out! The Sun's UV radiation can be nearly magnified twofold due to snow reflection.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

During September, Stanley experiences an average high-temperature of 62.1°F (16.7°C) and a low-temperature of 36.5°F (2.5°C).

What is the average humidity in September?

The average relative humidity in September is 53%.

How many days does it rain in September?

In Stanley, in September, it is raining for 9.5 days, with typically 1.18" (30mm) of accumulated precipitation.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 1.5 snowfall days, it receives 1.38" (35mm) of snow.

What is the average length of the day in September?

The average day length in September is 12h and 29min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 7:03 am and sunset at 8:15 pm. On the last day of the month, sunrise is at 7:37 am and sunset at 7:21 pm MDT.

How long on average sun shines in September?

The average sunshine duration in September is 9h.

What is the UV index intensity in September?

In September, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Stanley, ID

Average temperature in September - Stanley, ID
  • Average high temperature in September: 62.1°F

The warmest month (with the highest average high temperature) is July (72.7°F).
The month with the lowest average high temperature is December (23.9°F).

  • Average low temperature in September: 36.5°F

The month with the highest average low temperature is July (43.3°F).
The coldest month (with the lowest average low temperature) is December (5.4°F).

Average pressure in September
Stanley, ID

Average pressure in September - Stanley, ID
  • Average pressure in September: 29.96"Hg

The month with the highest atmospheric pressure is January (30.26"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Stanley, ID

Average wind speed in September - Stanley, ID
  • Average wind speed in September: 5mph

The windiest month (with the highest average wind speed) is July (5.8mph).
The calmest months (with the lowest average wind speed) are January and October (4.8mph).

Average humidity in September
Stanley, ID

Average humidity in September - Stanley, ID
  • Average humidity in September: 53%

The months with the highest relative humidity are February and March (91%).
The month with the lowest relative humidity is July (44%).

Average rainfall in September
Stanley, ID

Average rainfall in September - Stanley, ID
  • Average rainfall in September: 1.18"

The wettest month (with the highest rainfall) is March (2.17").
The driest months (with the least rainfall) are July and August (0.63").

Average rainfall days in September
Stanley, ID

Average rainfall days in September - Stanley, ID
  • Average rainfall days in September: 9.5 days

The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is January (3.1 days).

Average snowfall in September
Stanley, ID

Average snowfall in September - Stanley, ID
  • Average snowfall in September: 1.38"

The month with the highest snowfall is December (16.77").
The months with the least snowfall are July and August (0").

Average snowfall days in September
Stanley, ID

Average snowfall days in September - Stanley, ID
  • Average snowfall days in September: 1.5 days

The month with the highest number of snowfall days is March (21.6 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Stanley, ID

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

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

  • Average sunshine in September: 9h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The months with the least sunshine are January and December (Average sunshine: 4h and 24min).

Average sunshine days in September
Stanley, ID

Average sunshine days in September - Stanley, ID
  • Average sunshine days in September: 18.2 days

The month with the most sunshine days is July (20 days).
The month with the least sunshine days is April (8.1 days).

Average UV index in September
Stanley, ID

Average UV index in September - Stanley, ID
  • Average UV index in September: 2

The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, March and November (UV index 1).

Average cloud cover in September
Stanley, ID

Average cloud cover in September - Stanley, ID
  • Average cloud cover in September: 20

The month with the most cloud cover is February (Cloud cover 65).
The month with the least cloud cover is July (Cloud cover 12).

Average visibility in September
Stanley, ID

Average visibility in September - Stanley, ID
  • Average visibility in September: 6mi

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

Stanley, Idaho, USA

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