FORECAST SUMMARY: Saturday, July 18, 2026 through Sunday, July 19, 2026
Air Quality Alerts for Saturday and Sunday, July 18-19, 2026
The Michigan Department of Environment, Great Lakes, and Energy (EGLE) is issuing Air Quality Alerts for elevated levels of fine particulate (PM2.5) for Saturday and Sunday, July 18-19, 2026.
PM2.5: During Saturday, pollutants are expected to be Unhealthy (AQI Red) in the Upper Peninsula and USG (AQI Orange) in the Northern Lower Peninsula. The Southern Lower Peninsula has been downgraded to Moderate (AQI Yellow) and the Alert discontinued.
During Sunday, pollutants are expected to range between Unhealthy (AQI Red) in the Upper Peninsula to USG (AQI Orange) in the 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 during Saturday. Sunday will be a mix of mostly Good (AQI Green) to Moderate (AQI Yellow).
FORECAST DISCUSSION
Michiganders awoke to much improved conditions Saturday morning. Friday, however, was another extremely poor Air Quality day with 24-hour averages ranging from 213 ug/m3 at Lansing to 118 ug/m3 at Seney. Maximum hourly numbers ranged from 331 ug/m3 in Grand Rapids to 178 ug/m3 at Houghton Lake.
As discussed in yesterday’s forecast, enough sun did break through the smoke during Friday and ozone was an issue in certain locations. Several monitors crossed into the USG range and Muskegon topped the chart with Unhealthy at 103 ppb.
Saturday will be an overall improvement over the past few days, especially in the Lower Peninsula. Morning readings of the monitors show the entire Lower Peninsula in Moderate while the Upper Peninsula remains in the Unhealthy category. Conditions will stay mostly the same throughout the day, although the passing of a front will cause some fresh smoke to invade the state. Fortunately, latest model results have reduced the level of severity we can expect from that fresh smoke.
During Saturday, Alert levels have been reduced to Unhealthy in the Upper Peninsula and USG in the Northern Lower Peninsula. The Southern half of the Lower Peninsula has been downgraded to Moderate (AQI Yellow) and the Alert discontinued.
During Sunday, the changing winds from the passing front will lead to another statewide Alert, albeit not as severe as originally anticipated. The Upper Peninsula will remain Unhealthy and entire Lower Peninsula will be USG.
Ozone could spike in certain areas on Saturday is enough sun breaks through. The passing of the front should reduce that potential, during Sunday.
This trend looks to continue into Monday with most, if not all, the state under some level of Alert.
In the Alert areas, 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 Unhealthy and USG. Forecasts will continue to be updated frequently, to keep track of any unexpected changes.
Forecast updated by Jim Haywood: Saturday, July 18, 2026
Next forecast update: Sunday, July 19, 2026