September weather forecast
Post Falls, ID

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Corbin Park on the banks of the Spokane River flowing downstream in Post Falls, Idaho, USA
Corbin Park on the banks of the Spokane River flowing downstream in Post Falls, Idaho, USA

Weather in September

September in Post Falls brings in the beautiful hues of fall with a visible drop in temperature. This month records a decrease in the temperature high to 71.4°F (21.9°C) from the scorching 82°F (27.8°C) in August. The city witnesses a short-lived resurgence in rainfall before the drier months of October and November, enhancing the rich autumn colors. As daylight hours retract and temperatures dip, residents begin preparing for winter. September leaves behind gorgeous fall colors, paving the way for the advancing chill of October.

Temperature

September brings a drop in Post Falls's average high-temperature, falling from a warm 82°F (27.8°C) in August to an agreeable 71.4°F (21.9°C). Despite the hot September days, Post Falls's nights see an average temperature plunge to a chilly 45°F (7.2°C).

Humidity

In September, the average relative humidity in Post Falls is 58%.

Rainfall

In Post Falls, in September, during 8.4 rainfall days, 0.79" (20mm) of precipitation is typically accumulated. Throughout the year, there are 141.2 rainfall days, and 22.6" (574mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.31" (8mm) of snow. Throughout the year, there are 71.8 snowfall days, and 56.54" (1436mm) of snow is accumulated.

Daylight

In September, the average length of the day is 12h and 33min.
On the first day of September, sunrise is at 6:07 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:28 pm PDT.

Sunshine

The average sunshine in September is 9.8h.

UV index

In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the average person.
Note: A typical high UV index of 4 in September suggests the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.

Frequently asked questions

What is the usual temperature for Post Falls in September?

The average high-temperature and low-temperature during September are 71.4°F (21.9°C) and 45°F (7.2°C) respectively. The average heat index (a.k.a. 'real feel', 'felt air temperature'), which represents the influence of relative humidity on air temperature, in August is estimated at 82.4°F (28°C).

What is the average humidity in September?

The average relative humidity in September is 58%.

How much does it rain in September?

In Post Falls, in September, during 8.4 rainfall days, 0.79" (20mm) of precipitation is typically accumulated.

When does it start to snow?

September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.31" (8mm) of snow.

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

In September, the average day length is 12h and 33min.

What time are sunrise and sunset in September?

On the first day of September, sunrise is at 6:07 am and sunset at 7:27 pm. On the last day of the month, sunrise is at 6:46 am and sunset at 6:28 pm PDT.

How long on average sun shines in September?

In September, the average sunshine duration is 9.8h.

How high is the UV index in September?

In Post Falls, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate 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
Post Falls, ID

Average temperature in September - Post Falls, ID
  • Average high temperature in September: 71.4°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°F

The month with the highest average low temperature is August (51.8°F).
The coldest month (with the lowest average low temperature) is December (21.2°F).

Average pressure in September
Post Falls, ID

Average pressure in September - Post Falls, ID
  • Average pressure in September: 29.96"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
Post Falls, ID

Average wind speed in September - Post Falls, ID
  • Average wind speed in September: 4.1mph

The windiest month (with the highest average wind speed) is April (5mph).
The calmest month (with the lowest average wind speed) is December (3.9mph).

Average humidity in September
Post Falls, ID

Average humidity in September - Post Falls, ID
  • Average humidity in September: 58%

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

Average rainfall in September
Post Falls, ID

Average rainfall in September - Post Falls, ID
  • Average rainfall in September: 0.79"

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
Post Falls, ID

Average rainfall days in September - Post Falls, ID
  • Average rainfall days in September: 8.4 days

The month with the highest number of rainy days is March (17.5 days).
The month with the least rainy days is August (5.6 days).

Average snowfall in September
Post Falls, ID

Average snowfall in September - Post Falls, ID
  • Average snowfall in September: 0.31"

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
Post Falls, ID

Average snowfall days in September - Post Falls, ID
  • Average snowfall days in September: 0.2 days

The month with the highest number of snowfall days is December (16.9 days).
The months with the least snowfall days are June, July and August (0 days).

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

Average daylight in September / Average sunshine in September - Post Falls, ID
  • 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 5min

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 24min).

Average sunshine days in September
Post Falls, ID

Average sunshine days in September - Post Falls, ID
  • Average sunshine days in September: 19.8 days

The month with the most sunshine days is July (23.9 days).
The month with the least sunshine days is February (8.6 days).

Average UV index in September
Post Falls, ID

Average UV index in September - Post Falls, ID
  • 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
Post Falls, ID

Average cloud cover in September - Post Falls, ID
  • Average cloud cover in September: 23

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

Average visibility in September
Post Falls, ID

Average visibility in September - Post Falls, ID
  • Average visibility in September: 6mi

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

Post Falls, Idaho, USA

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