Weather in September
September in LaSalle, Illinois brings about the start of fall. As the days begin shortening to an average of 12.5 hours, summer's warmth gradually declines, leading to the cooler days of autumn. Colors begin to shift from the vibrant greens of summer to an array of fall hues. September’s mild temperatures and gently decreasing daylight hours pave the way for the more significant changes approaching in October.
On the first day of September, sunrise is at 6:23 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.
Temperature
The beginning of September brings a slight decrease in the average high-temperature, transitioning from 82.9°F (28.3°C) in August to a still warm 77°F (25°C). LaSalle reports a substantial plunge from daytime highs during the nights of September, with an average low-temperature of 52°F (11.1°C).Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:23 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.
Updated: Jun 9, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
In September, in LaSalle, the average high-temperature is 77°F (25°C), and the average low-temperature is 52°F (11.1°C).
How many hours of daylight does LaSalle have in September?
The average day length in September is 12h and 28min.
When are sunrise and sunset in September?
In September, on the first day of the month, sunrise is at 6:23 am and sunset at 7:28 pm. On the last day of the month, sunrise is at 6:52 am and sunset at 6:39 pm CDT.
Average temperature in September
LaSalle, IL
- Average high temperature in September: 77°F
The warmest month (with the highest average high temperature) is July (85°F).
The month with the lowest average high temperature is January (30°F).
- Average low temperature in September: 52°F
The month with the highest average low temperature is July (63°F).
The coldest month (with the lowest average low temperature) is January (14°F).
Average daylight in September
LaSalle, IL
- 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 12min).
LaSalle, Illinois, USA
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