Air Quality in Rapid City, South Dakota — Live
Live readings from PurpleAir sensors across Rapid City — with free alerts when west-side dust or Black Hills smoke moves in.
AQI 52 from 2 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Rapid City, South Dakota is AQI 52 — Moderate and falling — with PM2.5 at 10.0 µg/m³, the median of 2 live PurpleAir sensors reading 45 to 56. Canairy's verdict: Mostly clear.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Rapid City: weeds pollen is the strongest of the three at a high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Rapid City and Box Elder, Sturgis, Black Hawk, Piedmont. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Rapid City
The sensors Canairy reads in Rapid City are 11 AQI points apart right now, from Good to Moderate, which is the whole reason one city-wide number can mislead you: the median describes air you may not be standing in.
| From city center | AQI | Category |
|---|---|---|
| 2.2 mi N | 56 | Moderate |
| 4.3 mi WSW | 45 | Good |
Most of the year, Rapid City's air is genuinely good — this isn't a smoggy metro or a smoke-choked valley town. The two real exceptions are geography-specific: winter high-wind dust events on the west side of the city, and the occasional smoky stretch from a Black Hills fire or drifting Canadian wildfire smoke in summer.
What Canairy does for Rapid City
A clear verdict
Not just a number — a plain-English call for Rapid City: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Rapid City or across the country, on one screen.
Why west Rapid City gets its own dust advisories
Rapid City is split by a low ridge locals call the Gap, and the two sides aren't equal when it comes to air. West of the Gap is where most of the city's quarrying and heavy land-disturbance activity sits, and when strong winds pick up, that exposed soil turns into blowing dust. South Dakota's Department of Agriculture and Natural Resources tracks this under a Natural Events Action Plan written specifically for Rapid City, built to cut PM10 — coarse windblown dust — during high-wind stretches.
These alerts aren't a once-a-decade thing. DANR's own alert history clusters heavily in December and January — 16 alerts in 2021, 10 in 2023 — which lines up with Rapid City's Chinook winds, the warm, dry gusts that roll down off the Black Hills roughly 20 times a winter and can push a January afternoon into the 50s or 60s. When one of those windy stretches is forecast, the city's advisory (fronted publicly by city environmental planner Morgan Twombly) asks construction crews and quarry operators to water down sites and hold off on grading, and asks kids, older adults, and anyone with asthma to plan around it.
Wildfire smoke: Black Hills fires and Canadian drift
The forest around Rapid City burns more often than the city itself. The 2000 Jasper Fire tore through 83,508 acres near Jewel Cave in the southern Black Hills — still the largest wildfire in South Dakota history. The Legion Lake Fire started near Custer State Park in December 2017 and burned close to 54,000 acres, a reminder that Black Hills fire risk isn't confined to summer once conditions turn dry enough.
But the bigger, more frequent source of smoky days in Rapid City in recent years hasn't been a local fire at all — it's been smoke drifting down from Canada. In 2023, Canadian wildfire smoke gave the city hazy skies and moderate AQI readings, part of a pattern the state's own air monitoring flagged as pushing particle pollution higher across South Dakota that fire season.
What to actually do on a bad-air day
If you're on the west side of town, check the air before committing to an afternoon outside in winter — a clear morning can turn hazy by lunch once a Chinook starts moving dust around. If wildfire smoke is the driver instead, close windows early; fine smoke particles get indoors well before the air smells like a campfire.
Canairy reads the sensors near the places you've actually saved instead of one faraway monitor, so you get a number for your side of the Gap, not just downtown. Set your threshold once, and we'll tell you when it's crossed, and when it clears.
Rapid City air quality FAQ
What is the air quality in Rapid City right now?
As of September 14, 2026 at 8:59 AM MDT, the air quality in Rapid City, South Dakota is AQI 52 — Moderate — with PM2.5 at 10.0 µg/m³, the median of 2 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Why does west Rapid City get high-wind dust alerts?
West Rapid City sits across a low ridge called the Gap from downtown and is home to most of the city's quarrying and land-disturbance activity. When strong winds - often the same Chinook gusts that warm South Dakota winters - pick up loose soil on that side of town, the state's Department of Agriculture and Natural Resources issues a dust advisory under its Natural Events Action Plan for Rapid City, a pattern that shows up most winters between December and February.
Does Canadian wildfire smoke reach Rapid City?
Yes. In 2023, smoke drifting down from Canadian wildfires gave Rapid City hazy skies and moderate air quality readings, part of a broader pattern that pushed particle pollution across South Dakota that fire season. Local Black Hills fires, like the 83,508-acre Jasper Fire in 2000, can add to it depending on wind direction.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 2 curated PurpleAir sensors Canairy tracks in and around Rapid City, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
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Air quality near Rapid City
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