Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September ushers in a slight temperature change, with average high-temperatures reducing from August's moderately hot 85.8°F (29.9°C) to a still warm 76.3°F (24.6°C). The month of September records an average low-temperature of 55.9°F (13.3°C).Humidity
With an average relative humidity of 58%, September is the least humid month.Rainfall
In Iona, during September, the rain falls for 8.5 days and regularly aggregates up to 1.18" (30mm) of precipitation. Throughout the year, there are 107.6 rainfall days, and 17.83" (453mm) of precipitation is accumulated.Snowfall
May through September are months without snowfall.Daylight
The average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 7:02 am and sunset at 8:12 pm. On the last day of September, sunrise is at 7:34 am and sunset at 7:19 pm CDT.
Sunshine
In Iona, the average sunshine in September is 8.8h.UV index
In Iona, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: In September, an average UV index of 5 transforms into the following instructions:
Exercise prevention - Precautions against solar damage are endorsed. For skin protection, it's recommended to minimize Sun exposure during its peak hours around midday. 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
What is the average September temperature?
What is the least humid month?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Iona have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Iona have in September?
What is the UV index reading in September?
Average temperature in September
Iona, 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
Iona, 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
Iona, 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
Iona, 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
Iona, 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
Iona, 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
Iona, 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
Iona, 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
Iona, SD
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in September: 8h and 5min
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
Iona, 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
Iona, 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
Iona, 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
Iona, 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).
Iona, South Dakota, USA
Weather forecast for your location
2. Allow the app to use your location