Three extra problems
First, you have to find the fires. Satellites spot fires by detecting heat from space. But clouds can hide a fire from the satellite. So can thick smoke from another fire. A fire the satellite can't see is a fire the forecast doesn't know about.
Second, you have to guess the smoke. Nobody can measure exactly how much smoke a fire makes. Scientists estimate it from how hot the fire looks from space and what's burning underneath. Grass, pine forest, and swampy peat all burn differently and make different amounts of smoke.
Third, you ride the wind. Smoke goes wherever the wind carries it, sometimes more than a thousand miles. If the wind forecast is off by a little, the smoke ends up somewhere else. And height matters: smoke riding high in the sky might pass right over your town while the air at the ground stays clean. It's the low smoke you actually breathe.
Each step adds a little error, and the little errors multiply. That's why smoke forecasts are pretty sharp for the next day or two and get fuzzy after that, and why this site tells you when the models agree and when they don't.
What that means for the answer you get
It is why the forecast on this site leads with a clear time rather than a single number, and why the clear time requires six straight hours below the Hazy threshold before it will call anything. One hour of cleaner air inside a bad stretch is well within the error the three problems above produce. Six hours is a claim worth making.
It is also why the timeline marks the hours where the models split instead of drawing one confident line through them. Where two models put the smoke in different places at the same hour, that disagreement is the most honest thing we can show you, and hiding it behind an average would make a rough answer look precise.
Every hour on every page here is a model estimate, including the hours before now. Those are the model's account of the past, not measurements.
Where the numbers come from
Forecast: NOAA HRRR-Smoke, Copernicus CAMS, Open-Meteo. Fires: NIFC WFIGS. Thermal hotspots: NASA FIRMS.
Generated using Copernicus Atmosphere Monitoring Service information.
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.