Air Quality in Casper, Wyoming — Live

Live readings from PurpleAir sensors across Casper — with free alerts the moment the air changes, wind or no wind.

Live Casper AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Casper and Mills, Evansville, Bar Nunn, Glenrock.

Casper's air is good on most days, and the reason is the wind: central Wyoming is rarely still, and that near-constant airflow tends to clear out vehicle exhaust and refinery emissions before they can build up the way they might in a stiller valley. The exceptions are wildfire smoke that drifts in some weeks in late summer and fall — increasingly from fires burning in Canada as well as grass and timber fires closer to home in the Powder River Basin — and the HF Sinclair oil refinery that has operated inside city limits for more than a century.

Canairy watches the sensors around your home, your kids' school, and everywhere else you care about, and tells you in plain English when the air changes enough to matter.

Why Casper is usually one of the windier — and cleaner — cities in the country

Casper sits at 5,120 feet on the North Platte River, at the edge of open plains that run for miles in every direction. The city consistently ranks among the windiest in the United States, with average annual wind speeds around 12-13 mph and routine gusts of 40-50 mph, especially in spring, with December typically the windiest month of the year.

That constant airflow is generally good news for air quality. It disperses day-to-day sources — traffic on Interstate 25, the refinery near downtown — before they can concentrate the way pollution does in a wind-sheltered valley. Casper doesn't get the same nightly temperature-inversion buildup that traps smoke and exhaust in mountain-basin towns; the terrain here is too open and the wind too persistent for pollution to sit still for long.

The refinery that's been part of Casper since the oil boom

Casper is nicknamed "the Oil City," and the refinery a few blocks from downtown is not new. Companies began refining crude here as far back as the 1890s, tied to the Salt Creek Oil Field about 40 miles to the north, and the plant now operated as HF Sinclair's Casper Refinery — a roughly 250-acre, fully integrated facility processing about 30,000 barrels of crude a day — is a direct descendant of that history.

In August 2012, the EPA and Department of Justice announced that Sinclair Casper Refining Co. had violated a 2008 Clean Air Act consent decree by exceeding nitrogen oxide emissions limits and failing to properly operate a flare gas recovery system at its Casper and Sinclair, Wyoming refineries. The settlement required roughly $3.8 million in stipulated penalties, about $10.5 million in new pollution control equipment including a selective catalytic reduction system, and combined cuts of about 24 tons a year of NOx, 385 tons of sulfur dioxide, and 59 tons of particulate matter across the two plants — a reminder that the refinery is a real, measured part of what's in Casper's air, wind or no wind.

When wildfire smoke beats the wind

Even Casper's wind can't outrun a big enough smoke plume. In May and again in September 2023, smoke from wildfires burning in Canada settled over central Wyoming for days, dulling the sky and pushing fine-particle readings higher even on days that were sunny and calm at ground level.

The smoke doesn't have to travel that far to matter. In September 2024, air quality in Casper was rated unhealthy after grass and timber fires burning in Campbell and Johnson counties — a couple of hours northeast, in the Powder River Basin — drifted smoke into the city, and by early September 2025 the National Weather Service was again warning of hazy skies and elevated fire danger across central and southern Wyoming. Those are the stretches worth checking a sensor before you commit to an afternoon outside — not the several hundred other days a year when Casper's air is simply clean.

Casper air quality FAQ

What is the air quality in Casper right now?

This page shows the current AQI for Casper, calculated from PurpleAir sensors in and around the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood, from downtown out to Mills, Evansville, and Bar Nunn.

Why does Casper's air get smoky some years?

Casper's near-constant wind usually keeps the air clean, but it can't always outrun a big enough wildfire. Smoke from Canadian wildfires reached central Wyoming in both May and September 2023, and smoke from grass and timber fires in Campbell and Johnson counties, roughly two hours northeast in the Powder River Basin, pushed Casper's air quality to unhealthy levels in September 2024. Those weeks are the exception, not the rule.

Does the Casper oil refinery affect local air quality?

Yes, to a measurable degree. The HF Sinclair refinery near downtown has processed crude in Casper for more than a century, and in 2012 the EPA and Department of Justice found the company had exceeded nitrogen oxide limits and mismanaged a flare gas recovery system there, part of a settlement that required new pollution controls and cut combined NOx, SO2, and particulate emissions at its Wyoming plants. Casper's strong, near-constant winds disperse most day-to-day emissions quickly, but the refinery is a real, permitted source worth knowing about, especially if you live close to it.

What AQI level is unhealthy?

Under the US EPA scale, AQI 0-50 is Good and 51-100 is Moderate. From 101 the air is Unhealthy for Sensitive Groups - kids, older adults, and people with asthma or heart conditions - and above 150 it's Unhealthy for everyone. Canairy translates these numbers into a plain-English verdict, like whether to close the windows or move a workout indoors.

Is Canairy free?

Yes. The Canairy app is free to download and includes live air quality for all your saved places, plain-English verdicts, and free push alerts when the air crosses your threshold. A paid plan adds extras like SMS text alerts.

Where does Canairy's Casper data come from?

Readings come from PurpleAir's network of laser particle sensors across Casper and surrounding towns, cross-referenced with government monitors and the Google Air Quality API. You can see every sensor behind your numbers on the live map - there's no black box.

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