September weather forecastJefferson, IA
September
Weather in September
The first month of the autumn, September, is still a warm month in Jefferson, Iowa, with temperature in the range of an average high of 74.8°F (23.8°C) and an average low of 55.8°F (13.2°C).Temperature
Jefferson ushers in September with an average high-temperature of a still moderately hot 74.8°F (23.8°C), showing a close resemblance to the previous month. Jefferson witnesses a consistent average low-temperature of 55.8°F (13.2°C) throughout September.Humidity
The average relative humidity in September in Jefferson is 75%.Rainfall
In Jefferson, in September, during 11.2 rainfall days, 2.91" (74mm) of precipitation is typically accumulated. Throughout the year, there are 125.7 rainfall days, and 26.5" (673mm) of precipitation is accumulated.Snowfall
In Jefferson, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of the month, sunrise is at 6:43 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:14 am and sunset at 7:00 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In Jefferson, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: In September, a daily maximum UV index of 4 leads to the following instructions:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Jefferson, IA
- Average high temperature in September: 74.8°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (26.8°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in September
Jefferson, IA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Jefferson, IA
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in September
Jefferson, IA
- Average humidity in September: 75%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Jefferson, IA
- Average rainfall in September: 2.91"
The wettest month (with the highest rainfall) is May (4.06").
The driest month (with the least rainfall) is January (0.87").
Average rainfall days in September
Jefferson, IA
- Average rainfall days in September: 11.2 days
The month with the highest number of rainy days is June (17.3 days).
The month with the least rainy days is February (3.4 days).
Average snowfall in September
Jefferson, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (4.29").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Jefferson, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.8 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Jefferson, IA
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 18min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Jefferson, IA
- Average sunshine days in September: 17.2 days
The month with the most sunshine days is November (19.4 days).
The month with the least sunshine days is June (11.1 days).
Average UV index in September
Jefferson, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Jefferson, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).
Average visibility in September
Jefferson, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
