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
Saint Charles's weather in September involves a mild decrease in the average high-temperature, moving down slightly from August's 81.5°F (27.5°C) to a still moderately hot 75.4°F (24.1°C). Nighttime temperatures consistently average a mild 55.9°F (13.3°C) during September.Humidity
In September, the average relative humidity is 76%.Rainfall
In Saint Charles, in September, it is raining for 12.5 days, with typically 2.44" (62mm) of accumulated precipitation. In Saint Charles, during the entire year, the rain falls for 133 days and collects up to 26.14" (664mm) of precipitation.Snowfall
In Saint Charles, snow does not fall in June through September.Daylight
In Saint Charles, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:42 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:11 am and sunset at 6:58 pm CDT.
Sunshine
In September, the average sunshine is 9.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: In September, the UV index of 4 transforms into the following advice:
Ensure safety - Recommendations to avert sunburn are presented. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. During bright days, sunglasses that offer UVA and UVB defense are recommended.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How much does it rain in September?
When it does not snow in Saint Charles?
Does it snow in September?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Saint Charles, IA
- Average high temperature in September: 75.4°F
The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 55.9°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (15.3°F).
Average pressure in September
Saint Charles, 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
Saint Charles, IA
- Average wind speed in September: 8.1mph
The windiest month (with the highest average wind speed) is January (10.6mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in September
Saint Charles, IA
- Average humidity in September: 76%
The months with the highest relative humidity are January, February and June (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Saint Charles, IA
- Average rainfall in September: 2.44"
The wettest month (with the highest rainfall) is May (3.98").
The driest month (with the least rainfall) is January (0.91").
Average rainfall days in September
Saint Charles, IA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is June (17.9 days).
The months with the least rainy days are January and February (3.8 days).
Average snowfall in September
Saint Charles, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (4.53").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Saint Charles, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Saint Charles, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in September
Saint Charles, IA
- Average sunshine days in September: 15.9 days
The month with the most sunshine days is November (20.2 days).
The month with the least sunshine days is June (9.8 days).
Average UV index in September
Saint Charles, IA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (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
Saint Charles, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are July and September (Cloud cover 29).
Average visibility in September
Saint Charles, IA
- 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).
Saint Charles, Iowa, USA
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