September weather forecastNapa Junction, SD
September
Weather in September
The first month of the autumn, September, is still a warm month in Napa Junction, South Dakota, with temperature in the range of an average low of 55°F (12.8°C) and an average high of 76.1°F (24.5°C).Temperature
September's arrival aligns with a minor decrease in average high-temperatures, from August's warm 83.3°F (28.5°C) to a still moderately hot 76.1°F (24.5°C). The month of September records an average low-temperature of 55°F (12.8°C).Humidity
In Napa Junction, South Dakota, the average relative humidity in September is 67%.Rainfall
In Napa Junction, in September, during 11.6 rainfall days, 1.81" (46mm) of precipitation is typically accumulated. In Napa Junction, during the entire year, the rain falls for 117.9 days and collects up to 21.93" (557mm) of precipitation.Snowfall
In Napa Junction, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 29min.On the first day of September, sunrise is at 6:55 am and sunset at 8:03 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 7:12 pm CDT.
Sunshine
The average sunshine in September is 8.8h.UV index
The average daily maximum UV index in September in Napa Junction is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the average person.Note: A maximum daily UV index of 5 during September morphs into the following directions:
Undertake precautions - Guarding against sun damage is counselled. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Boost your sun resistance with garments that are densely woven yet spacious.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Napa Junction, SD
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in September: 55°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (12.9°F).
Average pressure in September
Napa Junction, SD
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Napa Junction, SD
- Average wind speed in September: 9.2mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.9mph).
Average humidity in September
Napa Junction, SD
- Average humidity in September: 67%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (64%).
Average rainfall in September
Napa Junction, SD
- Average rainfall in September: 1.81"
The wettest month (with the highest rainfall) is May (3.78").
The driest month (with the least rainfall) is February (0.59").
Average rainfall days in September
Napa Junction, SD
- Average rainfall days in September: 11.6 days
The month with the highest number of rainy days is June (17.4 days).
The month with the least rainy days is February (2.3 days).
Average snowfall in September
Napa Junction, SD
- Average snowfall in September: 0"
The month with the highest snowfall is December (2.95").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Napa Junction, SD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Napa Junction, SD
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 8h and 48min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in September
Napa Junction, SD
- Average sunshine days in September: 15.5 days
The month with the most sunshine days is November (21.5 days).
The month with the least sunshine days is June (9.3 days).
Average UV index in September
Napa Junction, 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 January (UV index 1).
Average cloud cover in September
Napa Junction, SD
- Average cloud cover in September: 26
The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is July (Cloud cover 25).
Average visibility in September
Napa Junction, 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).
