On October 3, 2026, a typical United States fire year still has 10% of its acreage ahead of it. The calendar reads late summer, and the fire record says a large share of the year's burning has not happened yet. That gap is the reason smoke keeps surprising people who have already filed the season under finished.
The season that is running right now
The Pacific Northwest is having its worst year on record. Oregon passed two million acres on August 3, breaking a record set only in 2024, and had reached about 2.4 million acres across roughly 1,600 fires by the third week of the month. Oregon and Washington together crossed three million acres on August 9. On August 5, an easterly flow pushed smoke over the Cascades and Portland briefly ranked among the most polluted major cities in the world.
None of that is over. NIFC's significant wildland fire potential outlook keeps all of Oregon and Washington above normal through September, and only turns below normal late in October. Canada is running a lighter year than 2025 but not a light one: the federal August update counted 4.1 million hectares burned and 582 active fires, which is the supply for most smoke episodes east of the Rockies.
Colorado is the useful counterexample. The Front Range has had no single dramatic smoke day this summer, which reads locally as a quiet year. It has still been smoky most of the summer, with monitors in the Unhealthy for Sensitive Groups range and 13 ozone action days. Chronic haze does not make the news the way a Code Purple day does, and it is easy to mistake the absence of an event for the absence of exposure.
What the calendar actually says
The curve at the top of this post is the fraction of a typical year's acreage that has burned by each date, built from seven years of national incident records. Read across it and the season looks longer than it feels:
| Date | Acres still ahead |
|---|---|
| Labor Day | 22% |
| Mid September | 17% |
| October 1 | 11% |
| Mid October | 7% |
| November 1 | 4% |
| December 1 | 1% |
Labor Day is not the finish line. It is closer to the three-quarter mark, with 22% of a normal year's acres still to burn. The remainder does not fall into single digits until roughly mid October, and 7% of a bad year is still a lot of smoke.
Rain ends a smoke season, not the calendar
Fire crews use the phrase season-ending event, and they mean something specific: enough precipitation, soon enough after enough cooling, that fuels stay wet rather than drying back out in three days. One rainy afternoon does not do it. A pattern change does. That is why the honest answer to "when does smoke season end" is regional.
- Pacific Northwest (Oregon, Washington): mid to late October, when the first genuine Pacific frontal systems return. West of the Cascades that switch usually flips hard and fast. East of them it can drag into November.
- Northern Rockies (Montana, Idaho): September, and at higher elevations sometimes late August. This is the earliest reliable close in the West, which is why Missoula and Glacier can go from very unhealthy to clear within a couple of weeks in early fall.
- Northern California and the Sierra: no clean ending. Fuels are at their driest of the year in September and October, and Diablo wind events run from September through November. The fire risk peak and the season's end overlap.
- Southern California: latest of all. Santa Ana winds become frequent in October and peak into December, and the season closes only when winter rain arrives. Los Angeles has a smoke risk window that runs past Thanksgiving in a dry year.
- Great Basin and Southwest (Nevada, Arizona, Utah): the monsoon usually breaks the desert season in July, but a weak monsoon leaves a long, dry shoulder into October.
- Canadian boreal: activity winds down through late September, though large fires can smolder well past that and put smoke into Minnesota, Wisconsin and the Northeast on any northwest flow.
Downwind cities inherit whichever of those calendars is upwind of them, which is why Denver can be smoky in late September from a fire in Idaho long after Colorado's own fires are out. The city guide lists where each place gets its smoke from.
Planning the next six weeks
Early fall is when the mismatch between expectation and exposure is widest. Trips get booked on the assumption that smoke season ended with summer: Labor Day weekend, September park visits, elk season, fall marathon training blocks, the shoulder-season hiking and riding that western states are best for. All of it lands inside the part of the curve that has not burned yet.
Practical version: check the 48-hour forecast the day before you go rather than the week before, since smoke is a wind problem and wind forecasts get good only inside about two days. Look at the ground monitors, not just the model. Move hard efforts to the clean window on the timeline instead of cancelling the day. Above an AQI of 150, back off the intensity, because heavy breathing is what actually determines your dose.
For a single episode rather than the season, the question is different and the answer is shorter: how to read a smoke forecast walks through getting a specific clearing hour for your own town.
Check the smoke forecast where you are →How this season compares →
Method & sources
- The season curve and every percentage on this page come from the day-of-year seasonality model in TrailSmoke's trends analysis, derived from the NIFC WFIGS incident record for fire years 2019 to 2025 (253,994 incidents). Each year is normalized to its own total before averaging, so one extreme season cannot dominate the shape. It tracks NIFC's own published same-day averages to within about 3%.
- It is a national curve. A regional curve would peak at different dates, which is what the regional section above describes qualitatively.
- Current-season figures are from the reporting linked inline and were accurate in late August. Season totals move; the percentages recalculate on every page load, the news figures do not.
- Outlooks: NIFC National Significant Wildland Fire Potential Outlook. Air quality: EPA AirNow.
TrailSmoke is not a health authority. During heavy smoke, follow guidance from AirNow and local officials.