The Infectious risk has stayed within a narrow range over the past 12 weeks, with the most recent week close to the 12-week average..
Allergy risk activity has stayed relatively flat over the past 12 weeks in McHenry, Illinois.
No Pollution activity has been reported over the past 12 weeks in McHenry, Illinois.
Weather risk activity has remained stable over the past 12 weeks in McHenry, Illinois.
Last updated: August 24, 2026
Data refreshed weekly