Bismarck
North Dakota, USA
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Bismarck, ND

An across the park view of the historical building of the State Capitol in Bismarck, North Dakota
An across the park view of the historical building of the State Capitol in Bismarck, North Dakota
The first month of the autumn, September, is also an agreeable month in Bismarck, North Dakota, with average temperature varying between 72.1°F (22.3°C) and 45°F (7.2°C).

Temperature

In September, the average high-temperature drops, from a warm 83.5°F (28.6°C) in August, to a pleasant 72.1°F (22.3°C). In Bismarck, in September, the average low-temperature is 45°F (7.2°C).

Humidity

In Bismarck, the average relative humidity in September is 63.7%.

Rainfall

In Bismarck, it is raining for 7.5 days, with typically 1.6" (40.4mm) of accumulated precipitation. Throughout the year, there are 97.7 rainfall days, and 17.9" (453.4mm) of precipitation is accumulated.

Snowfall

January through May, September through December are months with snowfall. September is the first month it typically snows in Bismarck. Throughout September, in the average 0.1 snowfall days, it receives 0.2" (5.1mm) of snow. Throughout the year, in Bismarck, North Dakota, there are 45.2 snowfall days, and 51.2" (1300.5mm) of snow is accumulated.

Daylight

In Bismarck, the average length of the day is 12.5h.

Sunshine

In Bismarck, North Dakota, the average sunshine is 8.2h.

UV index

The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unsafe exposure to the UV radiation for ordinary individuals.
Note: The daily maximum UV index of 5 in September interpret into the following advice:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the temperature in September in Bismarck?

The average high-temperature, in September, is 72.1°F (22.3°C), while the average low-temperature is 45°F (7.2°C).

What is the average humidity in September in Bismarck?

The average relative humidity in September is 63.7%.

How many days does it rain in September in Bismarck?

In Bismarck, North Dakota, during September, the rain falls for 7.5 days and regularly aggregates up to 1.6" (40.4mm) of precipitation.

When does it start snowing in Bismarck?

September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.2" (5.1mm) of snow.

What is the average length of the day in September in Bismarck?

The average length of the day in September is 12.5h.

How long on average sun shines in September in Bismarck?

The average sunshine in September in Bismarck, North Dakota, is 8.2h.

How high is the UV index in September in Bismarck?

In Bismarck, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unprotected exposure to the UV radiation.
Average temperature in September - Bismarck, ND
  • Average high temperature in September: 72.1°F

The warmest month (with the highest average high temperature) is July (84.7°F).
The month with the lowest average high temperature is January (23.4°F).

  • Average low temperature in September: 44.9°F

The month with the highest average low temperature is July (57.4°F).
The coldest month (with the lowest average low temperature) is January (2.2°F).

Average humidity in September - Bismarck, ND
  • Average humidity in September: 63.7%

The month with the highest relative humidity is December (74.5%).
The month with the lowest relative humidity is May (60.1%).

Average rainfall in September - Bismarck, ND
  • Average rainfall in September: 1.6"

The wettest month (with the highest rainfall) is June (3.2").
The driest month (with the lowest rainfall) is January (0.4").

Average rainfall days in September - Bismarck, ND
  • Average rainfall days in September: 7.5 days

The month with the highest number of rainy days is June (11.2 days).
The month with the lowest number of rainy days is October (6.6 days).

Average snowfall in September - Bismarck, ND
  • Average snowfall in September: 0.2"

The month with the highest snowfall is December (9.3").
Months with the lowest snowfall are June, July and August (0").

Average snowfall days in September - Bismarck, ND
  • Average snowfall days in September: 0.1 days

The month with the highest number of snowfall days is December (10 days).
Months with the lowest number of snowfall days are June, July and August (0 days).

Average daylight in September / Average sunshine in September - Bismarck, ND
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.8h).
The month with shortest days is December (Average daylight: 8.6h).

  • Average sunshine in September: 8.2h

The month with most sunshine is July (Average sunshine: 11.4h).
The month with least sunshine is December (Average sunshine: 4h).

Average UV index in September - Bismarck, ND
  • Average UV index in September: 5

Months with the highest UV index are June and July (UV index 8).
Months with the lowest UV index are January, November and December (UV index 1).