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
With the onset of September, Isabel's average high-temperature adjusts, receding from August's 84.7°F (29.3°C) to a still warm 75.4°F (24.1°C). Isabel's average low-temperature in the month of September is recorded at a mild 56.3°F (13.5°C).Humidity
August and September, with an average relative humidity of 49%, are the least humid months.Rainfall
In September, the rain falls for 7.9 days. Throughout September, 0.87" (22mm) of precipitation is accumulated. In Isabel, during the entire year, the rain falls for 99.7 days and collects up to 16.06" (408mm) of precipitation.Snowfall
In Isabel, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 31min.On the first day of the month, sunrise is at 6:08 am and sunset at 7:22 pm. On the last day of September, sunrise is at 6:43 am and sunset at 6:27 pm MDT.
Sunshine
In September, the average sunshine is 9.7h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: The UV index of 4 in September translates into these instructions:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What are the least humid months?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Isabel have in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Isabel have in September?
How high is the UV index in September?
Average temperature in September
Isabel, SD
- Average high temperature in September: 75.4°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (27°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (66°F).
The coldest month (with the lowest average low temperature) is January (13.6°F).
Average pressure in September
Isabel, SD
- Average pressure in September: 29.94"Hg
The months with the highest atmospheric pressure are January and February (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in September
Isabel, SD
- Average wind speed in September: 11.3mph
The windiest month (with the highest average wind speed) is April (12.2mph).
The calmest months (with the lowest average wind speed) are February and August (10.4mph).
Average humidity in September
Isabel, SD
- Average humidity in September: 49%
The month with the highest relative humidity is January (83%).
The months with the lowest relative humidity are August and September (49%).
Average rainfall in September
Isabel, SD
- Average rainfall in September: 0.87"
The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is January (0.51").
Average rainfall days in September
Isabel, SD
- Average rainfall days in September: 7.9 days
The month with the highest number of rainy days is May (14.7 days).
The months with the least rainy days are January and February (3.3 days).
Average snowfall in September
Isabel, SD
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.12").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Isabel, SD
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (12.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Isabel, SD
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 9h and 4min
The month with the most sunshine is July (Average sunshine: 11h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 48min).
Average sunshine days in September
Isabel, SD
- Average sunshine days in September: 20.4 days
The month with the most sunshine days is September (20.4 days).
The month with the least sunshine days is April (12.4 days).
Average UV index in September
Isabel, SD
- Average UV index in September: 4
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Isabel, SD
- Average cloud cover in September: 22
The month with the most cloud cover is January (Cloud cover 50).
The months with the least cloud cover are July and August (Cloud cover 19).
Average visibility in September
Isabel, 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).
Isabel, South Dakota, USA
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