Infectious risk activity has been decreasing over the past 12 weeks in McHenry, Illinois.
Allergy risk activity has been increasing 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 been increasing over the past 12 weeks in McHenry, Illinois.
Last updated: May 25, 2026
Data refreshed weekly