Weather for McHenry, Illinois
Current Weather
Five Day Weather Forecast
Tue
H: 90°F
L: 59°F
Wed
H: 82°F
L: 54°F
Thu
H: 67°F
L: 49°F
Fri
H: 75°F
L: 47°F
Sat
H: 66°F
L: 49°F
Air Quality
Nitrogen Dioxide: 22.95 μg/m3
Sulphur Dioxide: 2.65 μg/m3
Ozone: 60 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:19 PM
Daylight: 14 hrs 57 mins
Moon Transit: 9:37 PM
Moonset: 2:43 AM
Moon Phase: Waxing Gibbous
Moon Illumination: 76.9%
Best Times for Fishing or Hunting
Major Periods
9:01 AM - 11:31 AM9:07 PM - 11:37 PM
Minor Periods
3:33 PM - 5:03 PM2:13 AM - 3:43 AM
Action Rating: 2 out of 5
Air Quality Alert issued May 26 at 11:16AM CDT by NWS Chicago IL
Non-Weather Emergency Message. Not sent to IPAWS.
Effective: Tue May 26, 2026, 11:16 AM
Expires: Thu May 28, 2026, 12:00 AM
The Illinois Environmental Protection Agency has determined that an Air Pollution Action Day will be declared for the greater Chicago Metropolitan Area through Wednesday Night. A Chicago area Air Pollution Action Day is declared when weather conditions are such that widespread ozone and or particulate levels are expected to be at or above the Unhealthy for Sensitive Groups category of the Air Quality Index for multiple days. Ozone is expected to be the primary pollutant of concern. Active children and adults, especially people with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity. Area residents are urged to reduce pollution levels. Air quality forecasts, current air quality, and tips on how you can reduce your emissions can be found at www.airnow.gov. Media contact...Illinois EPA.
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.77 μg/m3
Sulphur Dioxide: 1.86 μg/m3
Ozone: 88.72 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:19 PM
Daylight: 14 hrs 57 mins
Moon Transit: 9:37 PM
Moonset: 2:43 AM
Moon Phase: Waxing Gibbous
Moon Illumination: 76.9%
Best Times for Fishing or Hunting
Major Periods
9:01 AM - 11:31 AM9:07 PM - 11:37 PM
Minor Periods
3:33 PM - 5:03 PM2:13 AM - 3:43 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 14.27 μg/m3
Sulphur Dioxide: 1.99 μg/m3
Ozone: 85.36 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:20 PM
Daylight: 14 hrs 58 mins
Moon Transit: 10:20 PM
Moonset: 3:03 AM
Moon Phase: Waxing Gibbous
Moon Illumination: 85.7%
Best Times for Fishing or Hunting
Major Periods
9:43 AM - 12:13 AM12:00 AM - 12:00 AM
Minor Periods
4:38 PM - 6:08 PM2:33 AM - 4:03 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 4.72 μg/m3
Sulphur Dioxide: 1.58 μg/m3
Ozone: 82.44 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:20 PM
Daylight: 15 hrs mins
Moon Transit: 11:05 PM
Moonset: 3:25 AM
Moon Phase: Waxing Gibbous
Moon Illumination: 92.7%
Best Times for Fishing or Hunting
Major Periods
10:26 AM - 12:56 AM12:00 AM - 12:00 AM
Minor Periods
5:43 PM - 7:13 PM2:55 AM - 4:25 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 9.83 μg/m3
Sulphur Dioxide: 1.79 μg/m3
Ozone: 74 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:21 PM
Daylight: 15 hrs 1 mins
Moon Transit: 11:51 PM
Moonset: 3:50 AM
Moon Phase: Waxing Gibbous
Moon Illumination: 97.4%
Best Times for Fishing or Hunting
Major Periods
11:12 AM - 1:42 PM12:00 AM - 12:00 AM
Minor Periods
6:47 PM - 8:17 PM3:20 AM - 4:50 AM
Action Rating: 4 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 9.5 μg/m3
Sulphur Dioxide: 1.56 μg/m3
Ozone: 69.92 μg/m3
Astronomical
Sun Transit: 12:50 AM
Sunset: 8:22 PM
Daylight: 15 hrs 2 mins
Moon Transit: 12:00 AM
Moonset: 4:21 AM
Moon Phase: Full
Moon Illumination: 99.8%
Best Times for Fishing or Hunting
Major Periods
12:00 AM - 12:00 AM12:00 AM - 2:30 PM
Minor Periods
7:50 PM - 9:20 PM3:51 AM - 5:21 AM
Action Rating: 4 out of 5