September weather forecastFort Thompson, SD
September
Weather in September
The first month of the autumn, September, is still a warm month in Fort Thompson, South Dakota, with an average temperature varying between 76.3°F (24.6°C) and 55.9°F (13.3°C).Temperature
September's onset brings a reduction in the average high-temperature, from a warm 85.8°F (29.9°C) in August to a still moderately hot 76.3°F (24.6°C). In the month of September, Fort Thompson witnesses a consistent average low-temperature of 55.9°F (13.3°C).Humidity
The least humid month is September, with an average relative humidity of 58%.Rainfall
In September, the rain falls for 8.5 days. Throughout September, 1.18" (30mm) of precipitation is accumulated. In Fort Thompson, during the entire year, the rain falls for 107.6 days and collects up to 17.83" (453mm) of precipitation.Snowfall
In Fort Thompson, snow does not fall in May through September.Daylight
In September, the average length of the day is 12h and 29min.On the first day of September, sunrise is at 7:01 am and sunset at 8:13 pm. On the last day of the month, sunrise is at 7:35 am and sunset at 7:19 pm CDT.
Sunshine
In September, the average sunshine is 8.8h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index of 5 during September translates into these guidelines:
Exercise prevention - Protecting skin and eyes from harm is required. Around midday, solar radiation is most harmful; hence, exposure should be limited. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Fort Thompson, SD
- Average high temperature in September: 76.3°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (26.1°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (66.2°F).
The coldest month (with the lowest average low temperature) is January (12.6°F).
Average pressure in September
Fort Thompson, SD
- Average pressure in September: 29.95"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 Thompson, SD
- Average wind speed in September: 10.3mph
The windiest month (with the highest average wind speed) is April (11.3mph).
The calmest month (with the lowest average wind speed) is August (9.1mph).
Average humidity in September
Fort Thompson, SD
- Average humidity in September: 58%
The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is September (58%).
Average rainfall in September
Fort Thompson, SD
- Average rainfall in September: 1.18"
The wettest month (with the highest rainfall) is June (3.03").
The driest month (with the least rainfall) is November (0.55").
Average rainfall days in September
Fort Thompson, SD
- Average rainfall days in September: 8.5 days
The month with the highest number of rainy days is May (15.3 days).
The month with the least rainy days is February (3.3 days).
Average snowfall in September
Fort Thompson, SD
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.66").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Fort Thompson, SD
- Average snowfall days in September: 0 days
The months with the highest number of snowfall days are January and February (11.7 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 Thompson, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 11h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).
Average sunshine days in September
Fort Thompson, SD
- Average sunshine days in September: 19.6 days
The month with the most sunshine days is November (20.7 days).
The month with the least sunshine days is April (11.8 days).
Average UV index in September
Fort Thompson, SD
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is February (UV index 1).
Average cloud cover in September
Fort Thompson, SD
- Average cloud cover in September: 23
The month with the most cloud cover is January (Cloud cover 49).
The month with the least cloud cover is August (Cloud cover 20).
Average visibility in September
Fort Thompson, SD
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
