FORECAST SUMMARY: Friday, July 17, 2026 through Saturday, July 18, 2026
Air Quality Alert for Friday and Saturday, July 17-18, 2026
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) is issuing a statewide Air Quality Alert for elevated levels of fine particulate (PM2.5) for Friday and Saturday, July 17-18, 2026.
PM2.5: During Friday, pollutants are expected to be Hazardous (AQI Maroon) in the Upper Peninsula and Very Unhealthy (AQI Purple) in the Lower Peninsula. During Saturday, pollutants are expected to vary between Very Unhealthy (AQI Purple) in the Upper Peninsula to USG (AQI Orange) in the southern Lower Peninsula.
Ozone: 8-hour average Ozone Particulate concentrations are expected to be mostly Moderate (AQI Yellow) but could have spikes in the USG (AQI Orange) range if enough sunlight breaks through.
FORECAST DISCUSSION
A statewide Air Quality Alert remains in place as Canadian wildfires, north of the Minnesota arrowhead continue to burn, out of control, and are spreading. A review of the Thursday monitor readings showed record breaking Air Quality issues. Daily 24-hour averages ranged from 385 ug/m3 at Marquette to 209 ug/m3 at Tecumseh. Daily hourly maximums ranged from 517 ug/m3 at Marquette to 285 ug/m3 in the Detroit area.
Friday could follow closely with similar numbers, but a passing warm front will put the Lower Peninsula in southwest winds late Friday and early Saturday. That change will allow some improvements, but we will still likely have recirculated smoke from Indiana and Illinois. That thinning of smoke could lead to elevated spikes in ozone levels if enough sun gets through.
This episode is not over, however. When the associated cold front passes through later Saturday, we will be back into northwest winds and more smoke. Those fires have not diminished, so we expect more bad Air Quality beginning late Saturday and into Sunday.
Saturday’s AQI forecast will range from Very Unhealthy in the Upper Peninsula to USG in the southern Lower Peninsula. Friday’s forecast remains Hazardous in the Upper Peninsula and Very Unhealthy in the Lower Peninsula.
The Saturday morning forecast will shed more light on what to expect for Sunday.
In the meantime, is recommended to avoid strenuous outdoor activities, especially those with heart disease and respiratory conditions like asthma. Watch for symptoms including wheezing, coughing, chest tightness, dizziness, or burning in nose, throat, and eyes. You can help reduce air pollution by limiting activities, such as outdoor burning. Keep windows closed overnight to prevent smoke from getting indoors and, if possible, run central air conditioning with MERV-13 or higher rated filters.
EXTENDED FORECAST:
Air Quality is expected to be to range between Very Unhealthy and USG. Forecasts will continue to be updated frequently this week, to keep track of any unexpected changes.
Forecast updated by Jim Haywood: Friday, July 17, 2026
Next forecast update: Saturday, July 18, 2026