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Lanark, IL Weather


Lanark, IL climate is warm during summer when temperatures tend to be in the 70's and very cold during winter when temperatures tend to be in the 20's.

The warmest month of the year is July with an average maximum temperature of 9.99 degrees Fahrenheit, while the coldest month of the year is January with an average minimum temperature of 7.50 degrees Fahrenheit.

Temperature variations between night and day tend to be moderate during summer with a difference that can reach 27 degrees Fahrenheit, and moderate during winter with an average difference of 22 degrees Fahrenheit.

The annual average precipitation at Lanark is 9.99 Inches. Rainfall in is fairly evenly distributed throughout the year. The wettest month of the year is June with an average rainfall of 4.77 Inches.

Weather Data

Normal Climate

Normal Temperatures

(MOUNT CARROLL Weather station, 7.52 miles from Lanark)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Max °F 28.9 34.6 46.7 60.2 72.1 81.6 85.1 83.1 75.8 63.8 47.3 33.9 59.4
Mean °F 18.2 23.6 35.6 47.4 58.9 68.0 72.0 69.8 61.6 49.8 36.7 23.9 47.1
Min °F 7.5 12.6 24.5 34.6 45.7 54.4 58.8 56.4 47.3 35.8 26.1 13.8 34.8

Normal Precipitation

(MOUNT CARROLL Weather station, 7.52 miles from Lanark)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Inch 1.43 1.52 2.63 3.67 4.34 4.77 3.83 4.54 3.48 2.73 2.84 2.02 9.99