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 sees a slight reduction in average high-temperature, with a shift from 82.8°F (28.2°C) in August to a still warm 77°F (25°C). During September, an average low-temperature of 58.3°F (14.6°C) is observed.Humidity
The average relative humidity in September in Old Saint Louis, Indiana, is 76%.Rainfall
The month with the least rainfall in Old Saint Louis, Indiana, is September, when the rain falls for 14.1 days and typically collects 1.73" (44mm) of precipitation.Snowfall
May through October are months without snowfall in Old Saint Louis.Daylight
In Old Saint Louis, the average length of the day in September is 12h and 26min.On the first day of the month, sunrise is at 7:12 am and sunset at 8:13 pm. On the last day of September, in Old Saint Louis, sunrise is at 7:38 am and sunset at 7:26 pm EDT.
Sunshine
The average sunshine in September is 8.4h.UV index
In September, the average daily maximum UV index in Old Saint Louis is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: In September, a regular UV index of 5 translates into these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. The Sun's radiation is especially intense around midday; try to stay in shade during this period. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September in Old Saint Louis?
What is the average humidity in September in Old Saint Louis?
What is the driest month in Old Saint Louis?
How much does it rain in Old Saint Louis in September?
When it does not snow in Old Saint Louis?
How many hours of daylight does Old Saint Louis have in September?
What time are sunrise and sunset in September in Old Saint Louis?
How many hours of sunshine does Old Saint Louis have in September?
How high is the UV index in September in Old Saint Louis?
Average temperature in September
Old Saint Louis, IN
- Average high temperature in September: 77°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 (35.2°F).
- Average low temperature in September: 58.3°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).
Average pressure in September
Old Saint Louis, IN
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Old Saint Louis, IN
- Average wind speed in September: 5.9mph
The windiest months (with the highest average wind speed) are January and February (8.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.3mph).
Average humidity in September
Old Saint Louis, IN
- Average humidity in September: 76%
The months with the highest relative humidity are January, February, July and December (81%).
The month with the lowest relative humidity is October (74%).
Average rainfall in September
Old Saint Louis, IN
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is May (3.5").
The driest month (with the least rainfall) is September (1.73").
Average rainfall days in September
Old Saint Louis, IN
- Average rainfall days in September: 14.1 days
The month with the highest number of rainy days is May (18.3 days).
The months with the least rainy days are January and February (9.4 days).
Average snowfall in September
Old Saint Louis, IN
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.17").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Old Saint Louis, IN
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Old Saint Louis, IN
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 8h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Old Saint Louis, IN
- Average sunshine days in September: 13.8 days
The month with the most sunshine days is October (17.7 days).
The month with the least sunshine days is May (10.3 days).
Average UV index in September
Old Saint Louis, IN
- Average UV index in September: 5
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, November and December (UV index 2).
Average cloud cover in September
Old Saint Louis, IN
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in September
Old Saint Louis, IN
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October and November (6mi).
The months with the lowest visibility are July and December (5mi).
Old Saint Louis, Indiana, USA
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