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's arrival coincides with a soft drop in the average high-temperature, subtly decreasing from August's warm 78.4°F (25.8°C) to a pleasant 72.9°F (22.7°C). Lanark's nighttime temperature in September falls to an average of 54.5°F (12.5°C).Humidity
In Lanark, the average relative humidity in September is 79%.Rainfall
In Lanark, during September, the rain falls for 10.7 days and regularly aggregates up to 1.5" (38mm) of precipitation. In Lanark, during the entire year, the rain falls for 130.8 days and collects up to 17.95" (456mm) of precipitation.Snowfall
In Lanark, snow does not fall in May through September.Daylight
The average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:56 am and sunset at 6:42 pm CDT.
Sunshine
In September, the average sunshine is 9h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Make use of precautions - It is urged to ward off sun damage. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September in Lanark?
What is the average humidity in September in Lanark?
How many days does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Lanark have in September?
How high is the UV index in September?
Average temperature in September
Lanark, IL
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is July (79.9°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in September: 54.5°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in September
Lanark, IL
- Average pressure in September: 30.03"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Lanark, IL
- Average wind speed in September: 7.6mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest month (with the lowest average wind speed) is August (6.5mph).
Average humidity in September
Lanark, IL
- Average humidity in September: 79%
The month with the highest relative humidity is January (87%).
The month with the lowest relative humidity is October (75%).
Average rainfall in September
Lanark, IL
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is May (2.76").
The driest months (with the least rainfall) are January and February (0.71").
Average rainfall days in September
Lanark, IL
- Average rainfall days in September: 10.7 days
The month with the highest number of rainy days is May (17.9 days).
The month with the least rainy days is February (4.4 days).
Average snowfall in September
Lanark, IL
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Lanark, IL
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (11.2 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
Lanark, IL
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).
Average sunshine days in September
Lanark, IL
- Average sunshine days in September: 17.8 days
The month with the most sunshine days is November (19.7 days).
The month with the least sunshine days is June (10 days).
Average UV index in September
Lanark, IL
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Lanark, IL
- Average cloud cover in September: 32
The month with the most cloud cover is January (Cloud cover 61).
The month with the least cloud cover is September (Cloud cover 32).
Average visibility in September
Lanark, IL
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Lanark, Illinois, USA
Weather forecast for your location
2. Allow the app to use your location