September weather forecast
Coeur d'Alene, ID

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Rocks, trees, and mountains on the shores of Lake Coeur d
Rocks, trees, and mountains on the shores of Lake Coeur d'Alene, in Idaho

Weather in September

September in Coeur d'Alene marks the beginning of the fall season with cooler temperatures. While the remnants of summer continue to influence the weather, a hint of autumn becomes more evident. Though the rainfall sees an increase up to 0.91" (23mm), the remaining summer warmth counteracts any chill. Fall colors start to dot the cityscape as the month progresses. While the daylight hours begin to shorten, the radiant September sunsets offer a mesmerizing display of earth tones.

Temperature

A subtle decrease in the average high-temperature marks September in Coeur d'Alene, falling from August's moderately hot 82°F (27.8°C) to an agreeable 72.1°F (22.3°C). A striking difference from the daytime highs is registered during September nights in Coeur d'Alene, Idaho, with an average temperature of 45.1°F (7.3°C).

Humidity

The average relative humidity in September is 57%.

Rainfall

In Coeur d'Alene, in September, it is raining for 8.3 days, with typically 0.91" (23mm) of accumulated precipitation. Throughout the year, there are 139.7 rainfall days, and 22.2" (564mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, in Coeur d'Alene, there are 71.6 snowfall days, and 56.26" (1429mm) of snow is accumulated.

Daylight

In September, the average length of the day in Coeur d'Alene is 12h and 33min.
On the first day of the month, sunrise is at 6:06 am and sunset at 7:26 pm. On the last day of September, sunrise is at 6:45 am and sunset at 6:27 pm PDT.

Sunshine

The average sunshine in September is 9.7h.

UV index

In Coeur d'Alene, the average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the ordinary person.
Note: In September, the UV index of 4 transforms into the following advice:
Take heed. Individuals of lighter complexion can be burned in less than half an hour. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration. Be aware! The intensity of the Sun's UV radiation can be amplified nearly twice due to snow reflection.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September in Coeur d'Alene?

In September, the average high-temperature and low-temperature are 72.1°F (22.3°C) and 45.1°F (7.3°C) respectively. The average heat index (a.k.a. 'real feel', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in August is evaluated at 82.4°F (28°C).

What is the average humidity in September in Coeur d'Alene?

The average relative humidity in September is 57%.

How many days does it rain in September in Coeur d'Alene?

In Coeur d'Alene, during September, the rain falls for 8.3 days and regularly aggregates up to 0.91" (23mm) of precipitation.

When does it start to snow in Coeur d'Alene?

September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.51" (13mm) of snow.

What is the average length of the day in September in Coeur d'Alene?

The average day length in September in Coeur d'Alene is 12h and 33min.

When are sunrise and sunset in September in Coeur d'Alene?

On the first day of September, sunrise is at 6:06 am and sunset at 7:26 pm. On the last day of the month, sunrise is at 6:45 am and sunset at 6:27 pm PDT.

How long on average sun shines in September in Coeur d'Alene?

In September, the average sunshine duration in Coeur d'Alene is 9.7h.

What is the UV index intensity in September in Coeur d'Alene?

In September, the average daily maximum UV index in Coeur d'Alene, Idaho, is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from unsafe exposure to Sun's UV rays.
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
Coeur d'Alene, ID

Average temperature in September - Coeur d
  • Average high temperature in September: 72.1°F

The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (31.3°F).

  • Average low temperature in September: 45.1°F

The month with the highest average low temperature is August (51.6°F).
The coldest month (with the lowest average low temperature) is December (20.8°F).

Average pressure in September
Coeur d'Alene, ID

Average pressure in September - Coeur d
  • Average pressure in September: 29.97"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

Average wind speed in September
Coeur d'Alene, ID

Average wind speed in September - Coeur d
  • Average wind speed in September: 4.1mph

The windiest month (with the highest average wind speed) is April (5.1mph).
The calmest month (with the lowest average wind speed) is December (3.7mph).

Average humidity in September
Coeur d'Alene, ID

Average humidity in September - Coeur d
  • Average humidity in September: 57%

The month with the highest relative humidity is January (93%).
The month with the lowest relative humidity is August (48%).

Average rainfall in September
Coeur d'Alene, ID

Average rainfall in September - Coeur d
  • Average rainfall in September: 0.91"

The wettest month (with the highest rainfall) is January (3.27").
The driest months (with the least rainfall) are July and August (0.43").

Average rainfall days in September
Coeur d'Alene, ID

Average rainfall days in September - Coeur d
  • Average rainfall days in September: 8.3 days

The month with the highest number of rainy days is March (17.5 days).
The month with the least rainy days is August (5.4 days).

Average snowfall in September
Coeur d'Alene, ID

Average snowfall in September - Coeur d
  • Average snowfall in September: 0.51"

The month with the highest snowfall is January (16.57").
The months with the least snowfall are June, July and August (0").

Average snowfall days in September
Coeur d'Alene, ID

Average snowfall days in September - Coeur d
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (16.5 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in September /
Average sunshine in September
Coeur d'Alene, ID

Average daylight in September / Average sunshine in September - Coeur d
  • Average daylight in September: 12h and 3min

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

  • Average sunshine in September: 9h and 4min

The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 3h and 18min).

Average sunshine days in September
Coeur d'Alene, ID

Average sunshine days in September - Coeur d
  • Average sunshine days in September: 20.1 days

The month with the most sunshine days is July (23.8 days).
The month with the least sunshine days is February (8.6 days).

Average UV index in September
Coeur d'Alene, ID

Average UV index in September - Coeur d
  • Average UV index in September: 4

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

Average cloud cover in September
Coeur d'Alene, ID

Average cloud cover in September - Coeur d
  • Average cloud cover in September: 23

The months with the most cloud cover are January and December (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 13).

Average visibility in September
Coeur d'Alene, ID

Average visibility in September - Coeur d
  • 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).

Coeur d'Alene, Idaho, USA

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