FORECAST SUMMARY: Friday, May 22, 2026 - Tuesday, May 26, 2026
Ozone: 8-hour average Ozone Particulate concentrations start the period in the Good (AQI Green) range. Moderate (AQI Yellow) is possible starting early next week.
PM-2.5: 24-hour daily average Fine Particulate concentrations in the Good range Friday and Saturday, could increase into the Moderate Sunday through the end of the forecast period.
FORECAST DISCUSSION:
High pressure will keep most of Friday dry and cool. As we head into the holiday weekend, an upper‑level system brings a few chances for rain. The best chance for showers arrives late Friday through Saturday as a couple of disturbances move through the region. Another weak system on Sunday may bring a few spotty showers or storms, but many areas will stay dry. For Memorial Day, high pressure returns, although a bit of afternoon instability could spark some isolated precipitation. Temperatures warm through the period: highs in the 60s on Friday rise into the 70s this weekend, reaching the 70s to low 80s early next week.
Air quality starts off in the Good category for both ozone and fine particulate levels. A cool easterly wind will help keep conditions Good through Saturday. By Sunday, winds weaken and shift to the west and southwest, and temperatures begin to rise. As we head into early next week, warmer weather is expected to contribute to increasing pollution levels. Moderate levels of ozone and fine particulates may develop as early as Sunday and could continue through Tuesday. While some locations will stay in the Good range, areas along the Lake Michigan shoreline and parts of southern Michigan are more likely to see Moderate air quality.
We do not expect fine particulate levels to rise above the Moderate range during this forecast period. It’s still too early to know exactly how high ozone levels may get, but based on current weather data, we do not anticipate ozone reaching higher than Moderate. We will continue to review forecast maps and pollution model guidance through the weekend. If conditions change and we believe an Air Quality Alert is needed for Monday or Tuesday, we will update the forecast accordingly.
EXTENDED FORECAST:
Moderate air quality could persist at times through the extended period.