September weather forecast
Fort Pierre, SD

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Weather in September

September marks the dawn of autumn, bringing noticeable changes to Fort Pierre's weather landscape. A significant drop in temperature is noticed, falling from highs of 86°F (30°C) in August to a still comfortable 76.8°F (24.9°C). This month brings shorter days and less intense sunshine, signaling the end of the summer season. A beautiful blend of warm and cool breezes makes September ideal for scenic outdoor activities in Fort Pierre. The last traces of summer linger in early September, gradually fading as the month progresses.

Temperature

As August shifts into September, a slight alteration in temperatures is observed, with average highs reducing from a hot 86°F (30°C) to a moderately hot 76.8°F (24.9°C). An average nighttime temperature of 57.4°F (14.1°C) is noted in Fort Pierre during the month of September.

Humidity

August and September, with an average relative humidity of 52%, are the least humid months.

Rainfall

In Fort Pierre, during September, the rain falls for 8.9 days and regularly aggregates up to 0.67" (17mm) of precipitation. Throughout the year, there are 98.5 rainfall days, and 13.7" (348mm) of precipitation is accumulated.

Snowfall

In Fort Pierre, snow does not fall in June through September.

Daylight

In September, the average length of the day is 12h and 30min.
On the first day of the month, sunrise is at 6:05 am and sunset at 7:17 pm. On the last day of September, in Fort Pierre, sunrise is at 6:39 am and sunset at 6:23 pm MDT.

Sunshine

The average sunshine in September is 9h.

UV index

In Fort Pierre, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for average individuals.
Note: The average daily UV index of 5 in September transforms into the following instructions:
Ensure safety - Sun damage prevention is strongly urged. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Updated: Aug 24, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in September in Fort Pierre?

The average high-temperature, in September, in Fort Pierre, is 76.8°F (24.9°C), while the average low-temperature is 57.4°F (14.1°C). In August, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, is evaluated at 87.8°F (31°C).

What is the least humid month?

August and September, with an average relative humidity of 52%, are the least humid months.

What is the average humidity in September?

The average relative humidity in September is 52%.

How much does it rain in September?

In September, the rain falls for 8.9 days. Throughout September, 0.67" (17mm) of precipitation is accumulated.

When it does not snow?

In Fort Pierre, snow does not fall in June through September.

Does it snow in September?

In Fort Pierre, South Dakota, in September, it doesn't snow. In October, it regularly snows.

What is the average length of the day in September?

In September, the average day length is 12h and 30min.

When is the sunrise / sunset in September?

On the first day of September, sunrise is at 6:05 am and sunset at 7:17 pm. On the last day of the month, sunrise is at 6:39 am and sunset at 6:23 pm MDT.

How long on average sun shines in September?

In Fort Pierre, the average sunshine duration in September is 9h.

What is the UV index reading in September?

In Fort Pierre, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health threat from 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
Fort Pierre, SD

Average temperature in September - Fort Pierre, SD
  • Average high temperature in September: 76.8°F

The warmest month (with the highest average high temperature) is July (88.7°F).
The month with the lowest average high temperature is January (26.2°F).

  • Average low temperature in September: 57.4°F

The month with the highest average low temperature is July (67.5°F).
The coldest month (with the lowest average low temperature) is January (12.6°F).

Average pressure in September
Fort Pierre, SD

Average pressure in September - Fort Pierre, SD
  • Average pressure in September: 29.94"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).

Average wind speed in September
Fort Pierre, SD

Average wind speed in September - Fort Pierre, SD
  • Average wind speed in September: 11.1mph

The windiest month (with the highest average wind speed) is April (11.9mph).
The calmest months (with the lowest average wind speed) are February and August (9.9mph).

Average humidity in September
Fort Pierre, SD

Average humidity in September - Fort Pierre, SD
  • Average humidity in September: 52%

The month with the highest relative humidity is January (85%).
The months with the lowest relative humidity are August and September (52%).

Average rainfall in September
Fort Pierre, SD

Average rainfall in September - Fort Pierre, SD
  • Average rainfall in September: 0.67"

The wettest month (with the highest rainfall) is May (2.24").
The driest month (with the least rainfall) is January (0.35").

Average rainfall days in September
Fort Pierre, SD

Average rainfall days in September - Fort Pierre, SD
  • Average rainfall days in September: 8.9 days

The month with the highest number of rainy days is June (14.2 days).
The month with the least rainy days is February (2.4 days).

Average snowfall in September
Fort Pierre, SD

Average snowfall in September - Fort Pierre, SD
  • Average snowfall in September: 0"

The month with the highest snowfall is February (3.66").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in September
Fort Pierre, SD

Average snowfall days in September - Fort Pierre, SD
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (10 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in September /
Average sunshine in September
Fort Pierre, SD

Average daylight in September / Average sunshine in September - Fort Pierre, SD
  • 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 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

Average sunshine days in September
Fort Pierre, SD

Average sunshine days in September - Fort Pierre, SD
  • Average sunshine days in September: 18.8 days

The month with the most sunshine days is November (22.3 days).
The month with the least sunshine days is June (13.7 days).

Average UV index in September
Fort Pierre, SD

Average UV index in September - Fort Pierre, SD
  • 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 February and December (UV index 1).

Average cloud cover in September
Fort Pierre, SD

Average cloud cover in September - Fort Pierre, SD
  • Average cloud cover in September: 21

The month with the most cloud cover is January (Cloud cover 50).
The months with the least cloud cover are July and August (Cloud cover 19).

Average visibility in September
Fort Pierre, SD

Average visibility in September - Fort Pierre, SD
  • 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).

Fort Pierre, South Dakota, USA

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