Vog in Hawaii — What It Is, When It's Bad, How to Plan

**Vog** = volcanic fog. It's the unique Hawaii-specific air pollution that happens whenever Kīlauea is actively erupting (which is most of the time) AND when the trade winds reverse so the SO₂ blows across the islands instead of out to sea. Most of the year, you won't notice it. A few weeks a year, it's heavy enough that asthma sufferers should stay indoors. ## The short answer | Season | Vog likelihood | Severity | |---|---|---| | Summer (May-Oct) | Low to moderate | Trade winds usually carry vog south, away from populated areas | | Winter (Nov-Mar) | Moderate to high | "Kona winds" reverse direction, pushing vog onto Kona, Kohala, Honolulu | | Always during eruption | Highest in Volcano area | Stay indoors if recommended | ## Where vog hits **The Big Island's west side (Kona, Kohala)** gets hit hardest because Kīlauea is on the southeast side and Kona winds blow vog westward + northward. **Honolulu gets vog on bad Kona-wind days** when SO₂ rides the wind 200 miles to Oʻahu. Visible as a yellowish haze on the horizon. **Maui** is least affected (further north). **Kauaʻi** rarely sees vog (furthest from Kīlauea). ## How to check the daily forecast Real-time air quality + vog forecast for Hawaii: - **vog.ivhhn.org** — The Interagency Hawaii Volcanic Hazard Network. Official. - **Hawaii Department of Health Air Quality** — airnow.gov, search "Hawaii" - **National Weather Service Honolulu** — weather.gov/hfo (forecast includes wind direction) Watch for: - Wind from the SOUTH or SOUTHEAST = vog blows toward populated areas. Bad. - Wind from the NORTHEAST (trade winds) = vog blows out to sea. Fine. ## What does vog actually feel like? Mild: nothing. Air looks slightly hazy. Maybe a faint sulfur smell. Moderate: scratchy throat, mild headache, watery eyes if you're outside all day. Asthma patients notice it. Severe (rare except in Volcano Village during major eruption): visible yellow tint to the sky, sulfur smell strong, hard to breathe outdoors. Schools sometimes hold indoor recess. ## Who should be cautious - People with asthma, COPD, or chronic respiratory conditions - Pregnant people - Young children (their lungs are still developing) - Heart-condition patients on high-vog days For everyone else: a few hazy days a year, no real harm. Many locals barely notice. ## How to protect yourself 1. **Check the forecast** — vog.ivhhn.org or local news 2. **Stay indoors** on red-flag days, especially with windows closed 3. **N95 mask helps** if you must be outside for extended periods 4. **HEPA air purifier** in the house if you live on the Big Island 5. **Stay hydrated** — water helps your respiratory system clear particulates 6. **Avoid heavy exercise** outdoors on bad days ## What Kīlauea is doing right now Kīlauea has been continuously active to some degree since 1983, with intermittent large summit eruptions. The Hawaiian Volcano Observatory (USGS) posts daily updates: **volcanoes.usgs.gov/observatories/hvo** Big eruption events in recent memory: - **2018** — Lower Puna eruption, ~700 homes destroyed, vog impacts Kona/Honolulu for months - **2020-2021** — Halemaʻumaʻu crater summit eruption (visible at Volcanoes National Park) - **2023+** — ongoing intermittent activity ## What to do during a major eruption If you're already on the Big Island: - Don't fly drones or get close to the eruption - Volcanoes National Park has the best safe viewing - The lava flow is dangerous. Respect closures. If you're planning to visit Hawaii during an eruption: - Air travel is generally safe. Big Island and Oʻahu air spaces stay open. - Hotel rooms in Hilo + Volcano Village may shift availability. - Tour operators around the eruption sites adjust routes daily. ## See current Big Island events + weather - [Big Island Things to Do →](/blog/big-island-things-to-do-2026) - [When Is Rainy Season in Hawaii →](/blog/when-is-rainy-season-in-hawaii) - [Browse all Big Island events →](/island/big-island)