Minnesota air quality

Stillwater, Minnesota Air Quality

Washington County45.056, -92.806

The nearest monitor to Stillwater, at Marine on St. Croix, 8 miles away, measured an index of 10 at Sun, 8:00 AM CDT, which is Good for ground-level ozone. Minnesota Pollution Control Agency forecasts Good for Twin Cities today and Good tomorrow.

Measured now
10 · Good
Today
— · Good
Tomorrow
— · Good
Pollutant
Ozone

Radar

Reflectivity now over Stillwater, Minnesota. Open it to see the particulate forecast on the map.

Open the live radar with the particulate forecast

Radar mosaic and map layers from NOAA MRMS and NOAA National Air Quality Forecast Capability. Boundaries from the Iowa Environmental Mesonet.

Alerts in force

An Air Quality Alert is issued by the National Weather Service on behalf of a state or local agency when pollution is expected to reach a level that harms health. An Air Stagnation Advisory means the air will not move enough to clear what is already in it.

None are in force near Stillwater right now. All Minnesota warnings.

Now

Good

Nearest monitor
Marine on St. Croix, 8 miles away (site 271636016)
Index measured
10 · Good
Measured at
Sun, 8:00 AM CDT
Ozone
11 ppb
Reporting area
Twin Cities, MN, 20 miles away
Reported by
Minnesota Pollution Control Agency
Area index
23 · Good

Measured, not modeled. AirNow observations are preliminary until the operating agency certifies them, which happens months later.

Today and tomorrow

Minnesota Pollution Control Agency's own forecast for Twin Cities, written by a forecaster rather than read off a model.

DayCategoryIndexPollutant
TodayGoodOzone
TomorrowGoodOzone
Tuesday, September 22GoodOzone
Wednesday, September 23GoodOzone

The forecaster’s discussion

Written by Minnesota Pollution Control Agency for Twin Cities and filed with AirNow.

Continued below normal temperatures and the lack of wind moving persistently from a source region of elevated concentrations of fine particle pollution into Minnesota means continued Green (good) AQI statewide through the weekend and into next week.

Hour by hour

NOAA’s National Air Quality Forecast Capability, bias-corrected against monitors, for this town’s own coordinate. The worst hour ahead is an index of 28, Good, around Tue, 6:00 PM CDT, from the run issued Sun, 1:00 AM CDT. This is a model, not a measurement.

HourIndexCategoryPM2.5Ozone
Sun, 3:00 AM CDT3Good0.7
Sun, 4:00 AM CDT3Good0.6
Sun, 5:00 AM CDT2Good0.3
Sun, 6:00 AM CDT2Good0.4
Sun, 7:00 AM CDT3Good1
Sun, 8:00 AM CDT4Good0.8
Sun, 9:00 AM CDT13Good114.4
Sun, 10:00 AM CDT14Good115.5
Sun, 11:00 AM CDT15Good216.9
Sun, 12:00 PM CDT17Good1.418.9
Sun, 1:00 PM CDT19Good0.720.9
Sun, 2:00 PM CDT20Good0.322.7
Sun, 3:00 PM CDT21Good0.323.8
Sun, 4:00 PM CDT22Good0.624.5
Sun, 5:00 PM CDT22Good0.524.9
Sun, 6:00 PM CDT22Good0.824.5
Sun, 7:00 PM CDT21Good123.7
Sun, 8:00 PM CDT20Good1.122.4
Sun, 9:00 PM CDT19Good1.121.1
Sun, 10:00 PM CDT18Good0.519.5
Sun, 11:00 PM CDT17Good118.3
Mon, 12:00 AM CDT16Good0.917.2
Mon, 1:00 AM CDT15Good0.516.3
Mon, 2:00 AM CDT14Good0.415.8
Mon, 3:00 AM CDT14Good0.815.4
Mon, 4:00 AM CDT13Good0.415
Mon, 5:00 AM CDT13Good0.514.2
Mon, 6:00 AM CDT12Good0.813.5
Mon, 7:00 AM CDT11Good0.912.6
Mon, 8:00 AM CDT10Good111.6
Mon, 9:00 AM CDT9Good110.5
Mon, 10:00 AM CDT8Good0.99.9
Mon, 11:00 AM CDT9Good0.910.2
Mon, 12:00 PM CDT9Good111
Mon, 1:00 PM CDT11Good112.4
Mon, 2:00 PM CDT13Good1.114.1
Mon, 3:00 PM CDT14Good115.9
Mon, 4:00 PM CDT16Good117.6
Mon, 5:00 PM CDT18Good119.4
Mon, 6:00 PM CDT19Good1.220.9
Mon, 7:00 PM CDT19Good1.521.2
Mon, 8:00 PM CDT19Good0.720.4
Mon, 9:00 PM CDT18Good119.3
Mon, 10:00 PM CDT16Good1.217.3
Mon, 11:00 PM CDT14Good0.815
Tue, 12:00 AM CDT11Good1.412.8
Tue, 1:00 AM CDT9Good1.410.5
Tue, 2:00 AM CDT7Good1.18
Tue, 3:00 AM CDT6Good0.56.3
Tue, 4:00 AM CDT5Good0.85.2
Tue, 5:00 AM CDT4Good0.74
Tue, 6:00 AM CDT4Good0.93.4
Tue, 7:00 AM CDT4Good0.83.3
Tue, 8:00 AM CDT4Good0.63.1
Tue, 9:00 AM CDT3Good0.43.9
Tue, 10:00 AM CDT5Good0.75.3
Tue, 11:00 AM CDT6Good0.77.3
Tue, 12:00 PM CDT9Good0.510.3
Tue, 1:00 PM CDT12Good0.613.6
Tue, 2:00 PM CDT16Good1.117.2
Tue, 3:00 PM CDT19Good4.420.9
Tue, 4:00 PM CDT22Good3.124.8
Tue, 5:00 PM CDT25Good0.927.9
Tue, 6:00 PM CDT28Good0.930
Tue, 7:00 PM CDT28Good1.130.4
Tue, 8:00 PM CDT27Good1.429
Tue, 9:00 PM CDT25Good1.127.3
Tue, 10:00 PM CDT23Good0.825.2
Tue, 11:00 PM CDT20Good1.123
Wed, 12:00 AM CDT18Good1.220
Wed, 1:00 AM CDT15Good1.116.9

Fine particles in micrograms per cubic meter, ozone in parts per billion as an 8-hour average. The index for each hour is EPA’s: the ozone figure is already the 8-hour average the ozone index is defined on, and the particle figure is run through EPA’s NowCast, which is how an hourly PM2.5 concentration becomes an index.

Smoke

NOAA’s analysts have not drawn smoke over Stillwater in satellite imagery today.

NOAA’s model forecasts no measurable smoke near the ground here over the next two days.

Smoke on the radar over Stillwater

What this means

Good

Air quality is satisfactory, and air pollution poses little or no risk.

Who is affected
Nobody is expected to be affected.
What to do
It is a good day to be outside.
Index range
0 to 50

Category descriptions are the Environmental Protection Agency’s own.

What these numbers are. An index beside a monitor’s name is a measurement, published hourly by AirNow and preliminary until the operating agency certifies it. A category for today or tomorrow is a state or local agency forecaster’s own forecast for a reporting area. An hourly index is NOAA’s air quality model on a five-kilometer grid, not a reading from any instrument. Where a town has no monitor within reach, only the model figures appear, and the page says so.

Nearby

The nearest towns with a page of their own, closest first.

Weather forecast for StillwaterWarnings in Washington CountyLive radar over StillwaterMinnesota air quality

Sources

Observations and daily forecasts from AirNow, the US Environmental Protection Agency’s program with NOAA, the National Park Service, NASA, tribal, state and local agencies. Hourly forecasts from NOAA’s National Air Quality Forecast Capability. Smoke analysis from NOAA’s Hazard Mapping System. Alerts from the National Weather Service. Index categories and breakpoints are EPA’s, as revised in 2024.