McHenry (IL) Weather & Climate: Best Time to Visit

Visitors to McHenry can expect significant temperature changes throughout the year. Average daytime temperatures reach a comfortable 28°C (82°F) in July. In January, the coolest month of the year, temperatures drop to a very cold -2°C (28°F).

At night, temperatures range from around 16°C (61°F) in July to -11°C (12°F) in January.

Check out our detailed temperature page for more information.

Temperature ranges by month

Generally, McHenry experiences moderate precipitation patterns, averaging 996 mm (39 in) yearly. McHenry can be quite wet during June, receiving approximately 133 mm (5.2 in) of precipitation over 13 rainy days.

In contrast, during the driest month (January), you will experience much drier conditions, with 38 mm (1.5 in) of precipitation spread across 9 snowy days. For more details, please visit our McHenry Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

McHenry can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 10.6 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 3.6 hours of sunlight per day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in McHenry.

The city experiences its highest humidity in December, reaching 76%. In May, the humidity drops to its lowest level at 64%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year