Air Quality in Hilo, Hawaii — Live
Live readings from PurpleAir sensors across Hilo — with free alerts the moment vog rolls in.
AQI 7 from 2 PurpleAir sensors · Holding steady · data from PurpleAir
As of , the air quality in Hilo, Hawaii is AQI 7 — Good and holding steady — with PM2.5 at 1.3 µg/m³, the median of 2 live PurpleAir sensors reading 3 to 11. Canairy's verdict: Breathe easy.
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 Hilo: grass pollen is the strongest of the three at a none 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 Hilo and Keaau, Pahoa, Pepeekeo, Volcano. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Hilo
The sensors Canairy reads in Hilo agree right now — all 2 sit in the Good band, a 8-point spread — so the city-wide number is a fair description of the whole area today.
| From city center | AQI | Category |
|---|---|---|
| 3.5 mi WSW | 11 | Good |
| 10.8 mi SE | 3 | Good |
Hilo sits on the windward side of the Big Island, facing straight into the northeast trade winds that blow onshore most days of the year and wring out roughly 126 inches of rain annually — enough to make it one of the wettest cities in the United States. That combination of onshore wind and near-daily rain is normally very good news for the air: the trade winds carry Kilauea's volcanic plume away toward the Kona side of the island instead of into the city, and the rain rinses out whatever fine particles are left. The exception is a wind reversal — locals call it a Kona wind day — when the flow turns southerly and vog that would normally miss Hilo gets carried back over it instead.
What Canairy does for Hilo
A clear verdict
Not just a number — a plain-English call for Hilo: 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 Hilo or across the country, on one screen.
Hilo's air is usually clean because of where it sits
Hilo faces directly into the trade winds, which blow out of the northeast on the large majority of days each year. That onshore flow, combined with the rain it wrings out of the moist air rising against Mauna Kea and Mauna Loa, is why Hilo averages around 126 inches of rain a year — among the highest totals of any city in the country. The same wind that brings the rain also carries Kilauea's gas plume away from the city and out toward the southwest, which is why the Kona coast, not Hilo, is normally the side of the island dealing with vog.
That geography is also why Hilo's air can look completely different from Kailua-Kona's on the same afternoon. A Kona-side town can be socked in with a thick haze while Hilo, sitting upwind of the volcano and getting rained on, reads clean. It's a reminder that a statewide vog forecast doesn't tell you what your own neighborhood is breathing — wind direction on a given day matters more than an island-wide average.
When the wind turns south, vog reaches Hilo too
Hilo's usual advantage disappears during Kona wind days, when the trade winds stall and the flow turns southerly. Instead of being carried away from the city, gas from Kilauea's summit and East Rift Zone gets pushed back to the northeast, over Puna and into Hilo itself. These reversals are irregular and typically short-lived, but they're the reason longtime residents check the wind forecast as closely as the vog forecast.
The 2018 eruption showed how close the source really is. Kilauea's lower East Rift Zone opened up in Leilani Estates, roughly 30 miles southeast of Hilo in the Puna district, on May 3, 2018. Over the following months lava destroyed more than 700 homes and erased the community of Kapoho, and venting fissures released enough sulfur dioxide that Hawaii County Civil Defense warned first responders and nearby residents of dangerous gas levels. Puna sits directly between Kilauea and Hilo, so even an ordinary trade-wind day during that eruption could carry a heavier dose of vog into South Hilo than the city usually sees.
Hilo has two active volcanoes as neighbors, not one
Mauna Loa, visible from Hilo alongside Kilauea, erupted in November 2022 for the first time since 1984, sending lava down its Northeast Rift Zone toward Saddle Road. The flow stopped about 1.7 miles short of the highway, but the eruption still reached the windward side in a different way: strands of volcanic glass known as Pele's hair drifted downwind and were reported as far as Laupahoehoe, a Hamakua coast town north of Hilo.
With both Kilauea and Mauna Loa capable of sending gas or ash toward the windward side under the right wind, Hilo's normally excellent air quality is really a function of the trade winds holding steady — which is most of the time, but not always. That's the kind of change that's easy to miss if you're going by memory of what the sky usually looks like instead of an actual reading.
Hilo air quality FAQ
What is the air quality in Hilo right now?
As of September 14, 2026 at 5:09 AM PDT, the air quality in Hilo, Hawaii is AQI 7 — Good — with PM2.5 at 1.3 µg/m³, the median of 2 live PurpleAir sensors. Open the windows. Great for outdoor activity.
Why does Hilo get vog sometimes if the trade winds usually blow it away?
Hilo sits upwind of Kilauea most of the year, so the normal northeast trade winds carry the volcano's gas plume out toward the Kona coast instead of over the city. But during Kona wind events — when the trade winds stall and the flow turns southerly — that plume can reverse and drift back up over Puna and into Hilo. These reversals are irregular, which is why a wind-direction check matters as much as a vog forecast.
Does Hilo's rain actually clean the air?
Yes. Hilo averages around 126 inches of rain a year, among the highest totals of any US city, and that near-daily rain rinses fine particles out of the air alongside the steady onshore trade winds. It's a big part of why Hilo's air quality is normally excellent even though two active volcanoes, Kilauea and Mauna Loa, sit within roughly 30 miles of the city.
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 Hilo, 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 Hilo
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