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
As Iona enters September, the average high-temperature decreases from the 85.8°F (29.9°C) of August to a still moderately hot 76.3°F (24.6°C). In the month of September, Iona experiences an average low-temperature of 55.9°F (13.3°C).Humidity
September is the least humid month, with an average relative humidity of 58%.Rainfall
In Iona, South Dakota, in September, during 8.5 rainfall days, 1.18" (30mm) of precipitation is typically accumulated. In Iona, during the entire year, the rain falls for 107.6 days and collects up to 17.83" (453mm) of precipitation.Snowfall
In Iona, snow does not fall in May through September.Daylight
In September, the average length of the day in Iona 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
The average sunshine in September in Iona 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 unprotected exposure to Sun's UV rays for average individuals.Note: The maximum daily UV index of 5 in September converts into the following recommendations:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Frequently asked questions
What are the temperatures in Iona in September?
What is the least humid month in Iona?
What is the average humidity in September in Iona?
How many days does it rain in September in Iona?
When it does not snow in Iona?
Does it snow in Iona in September?
What is the average length of the day in September in Iona?
When is the sunrise / sunset in September in Iona?
How long on average sun shines in September in Iona?
How high is the UV index in September in Iona?
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
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