Smoke forecast
Where the smoke over Pittsburgh was, and where the model sends it next. Scrub back 12 hours or forward 48. Every hour shown is a model estimate, not a measurement.
The scale is anchored to visibility, because that is the one reading you can take yourself without trusting a model. Distances are approximate.
From the Mount Washington overlook the Golden Triangle is sharp below, the Cathedral of Learning reads clean three miles east, and the river valleys hold their far bends.
The Cathedral of Learning has gone flat, and the Allegheny and Monongahela valleys lose their far ends into grey.
From Mount Washington the downtown towers still separate but the hills behind them, three miles out, have become one silhouette.
The Point holds from the overlook, under a mile below, while the tops of the tallest downtown buildings fade.
The top of the US Steel Tower goes. From Mount Washington you can lose the Golden Triangle a half mile below you.
Pittsburgh gets Canadian smoke on northerly flow from Ontario and Quebec, but the city has a second problem that makes it unusual: river valley inversions. Cool air settles into the valleys overnight and caps them, holding whatever is in the air at ground level well into the morning. That means a smoke plume that would pass over a flatter city can sit here.
The inversion behavior predates wildfire smoke by a century and is the reason Pittsburgh has an air quality culture at all. June 2023 layered Quebec smoke on top of it and produced some of the worst readings in the country.
Pittsburgh's valley fog and inversion haze predate wildfire smoke by a century. Cool air settles into the river valleys overnight and holds moisture and local emissions at ground level well into the morning, which flattens the view from Mount Washington on days with clean regional air. Fog burns off by late morning. Smoke does not.
The verdict at the top of this page answers that for Pittsburgh specifically, and it is reading the valley floor rather than the plateau. That is the number that matters here: cool air settles into the river valleys overnight and caps them, so the air down at the Point and the air up on the ridge can be two different readings at the same hour. Everything shown is a model estimate rather than a measurement at your address.
That is the headline answer above: the clear time, the first stretch of at least six straight hours below the Hazy threshold. Pittsburgh is the eastern city where that answer is least about the wind. The valleys cap themselves overnight and hold whatever is in them well into the morning, so a plume that would have passed over a flatter city sits here, and the clear time has to wait for the cap to break, not just for the flow to change.
Two mechanisms, and the honest answer is often both at once. The smoke comes from Ontario and Quebec on northerly flow, the same as the rest of this corridor. The valleys then keep it. June 2023 is the local marker precisely because it layered Quebec smoke on top of an inversion and produced some of the worst readings in the country. The fire was in Canada, but the reason it was that bad here was the terrain.
Ontario and Quebec, on northerly flow. Cleveland sits upwind across Lake Erie and Detroit sits upwind on northwesterly setups, both a day or so ahead, and both are linked below. What Pittsburgh adds is not a source but a trap: the inversion behaviour predates wildfire smoke by a century and is the reason this city has an air quality culture at all. Run the timeline backward on the map to see the plume arrive.
The five-day strip above gives the day-by-day read and the timeline covers forty-eight hours hour by hour. The pattern to watch for in Pittsburgh is mornings: an inversion means the day often starts worse than it ends, so a bad 7am reading is not necessarily a bad afternoon. Forecasts are sharpest one to two days out and the page shows where the models disagree.
Mount Washington is the vantage and it gives you two axes: out to the Cathedral of Learning three miles east, and down into the Allegheny and Monongahela valleys to see whether their far bends still hold. Then whether the hills behind downtown have become one silhouette. One local caveat the other cities on this corridor do not need: valley fog does all of this too, and the difference is that fog burns off by late morning and smoke does not.
Where Pittsburgh's smoke usually shows up first, and the places that share its air.
Ontario smoke crossing Lake Erie hits the Cleveland shoreline before it reaches the Allegheny plateau and settles into the valleys here.
On northwesterly flow the same Ontario plume passes Detroit a day or so ahead of the Pittsburgh river valleys.
Most smoke in the eastern half of the continent is Canadian, and it is old by the time it arrives.
Smokeshow is for informational and educational purposes only. It is not health, medical, or safety advice. Forecasts are model estimates and can be wrong, sometimes by a lot. Descriptions of what you might smell, see, or feel are generalizations, not predictions about your body. For decisions about your health, outdoor activity, or air quality safety, rely on official sources like AirNow.gov, the National Weather Service, and your local health authorities, and talk to a medical professional about your own situation.