Air Quality in Hilo, Hawaii — Live

Live readings from PurpleAir sensors across Hilo — with free alerts the moment vog rolls in.

Live Hilo AQI from nearby PurpleAir sensors loads when this page opens in a browser, along with a live sensor map covering Hilo and Keaau, Pahoa, Pepeekeo, Volcano.

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.

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.

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?

This page shows the current AQI for Hilo, calculated from PurpleAir sensors across the city and updated continuously. The map below shows every live sensor, so you can check the reading closest to your own neighborhood.

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 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.

Where does Canairy's Hilo data come from?

Readings come from PurpleAir's network of laser particle sensors across Hilo and surrounding Hawaii Island communities, 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.

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.

Get Canairy free on Google Play.