Is the air in Seattle safe today?

For most people, yes. Right now the US AQI in Seattle is 62, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.

When is the best time to be outside in Seattle?

Sat 6:00 AM–9:00 AM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 29. The worst hour is around Fri 11:00 AM, at 69.

What is the main pollutant in Seattle?

Fine particles (PM2.5). It drives the index right now, at 15 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.

How does Seattle's air compare with the WHO guideline?

Within the guideline. Over the next 24 hours PM2.5 averages about 11 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. The other pollutants stay within their guideline levels.

How many cigarettes is a day of Seattle's air?

About 0.5 cigarettes. Over the next 24 hours PM2.5 averages about 11 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.

Will air quality in Seattle improve this week?

Saturday looks cleanest. Its AQI peaks at 54, against 69 on Friday, the worst day in the forecast.

Seattle air quality

Washington, United States · Live AQI and hourly forecast for the next 5 days · valid Fri 9:00 AM local time

Moderate

US AQI, mostly PM_2.5

Model estimate. Nearby measurements are shown separately.

Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.

Next 24 hours: 28–69US AQI, highest around Fri 11:00 AM
Best time outside: Sat 6:00 AM–9:00 AMUS AQI about 29
PM_2.5 vs WHO guideline: 0.7×11 µg/m³ over 24 h, guideline 15
Cigarette equivalent: ≈ 0.5 a dayBerkeley Earth rule of thumb

Loading the live globe…

The live globe, centred on Seattle. Switch pollutants, drag through the next 5 days or press play. Full map →

Pollutants in Seattle right now

Pollutant	Now	Level	Next 24 h vs WHO
Fine particles PM_2.5	15 µg/m³	Moderate	0.7×
Coarse particles PM₁₀	16 µg/m³	Good	0.3×
Nitrogen dioxide NO₂	33 µg/m³	Good	0.8×
Ozone O₃	21 µg/m³	Good	0.6×
Sulphur dioxide SO₂	1.0 µg/m³	Good	0.0×
Carbon monoxide CO	229 µg/m³	Good	0.1×
Aerosol optical depth	0.10	Whole atmosphere · dimensionless
Desert dust	1 µg/m³	Modelled surface dust
UV index	0	Low

“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM_2.5, 45 for PM₁₀, 25 for NO₂, 40 for SO₂ and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline. Levels follow the US AQI, which is far less strict than the WHO, so air rated Good can still be above a guideline.

Next 48 hours

Hourly US AQI. Highest 69 around Fri 11:00 AM, lowest 24 around Sun 2:00 AM.

Good 0–50Moderate 51–100Sensitive 101–150Unhealthy 151–200Very unhealthy 201–300Hazardous 301+

5-day air quality forecast for Seattle

Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 150.

Day	US AQI	At worst	Worst hour	PM_2.5 avg	UV max
Fri, Nov 13	51–69	Moderate	11:00 AM	14	1 Low
Sat, Nov 14	27–54	Moderate	12:00 AM	5.3	1 Low
Sun, Nov 15	24–56	Moderate	11:00 PM	5.2	1 Low
Mon, Nov 16	38–62	Moderate	8:00 PM	11	1 Low
Tue, Nov 17	38–58	Moderate	8:00 AM	9.3	1 Low

Common questions about the air in Seattle

Is the air in Seattle safe today?
For most people, yes. Right now the US AQI in Seattle is 62, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.
When is the best time to be outside in Seattle?
Sat 6:00 AM–9:00 AM. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 29. The worst hour is around Fri 11:00 AM, at 69.
What is the main pollutant in Seattle?
Fine particles (PM_2.5). It drives the index right now, at 15 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.
How does Seattle's air compare with the WHO guideline?
Within the guideline. Over the next 24 hours PM_2.5 averages about 11 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. The other pollutants stay within their guideline levels.
How many cigarettes is a day of Seattle's air?
About 0.5 cigarettes. Over the next 24 hours PM_2.5 averages about 11 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in Seattle improve this week?
Saturday looks cleanest. Its AQI peaks at 54, against 69 on Friday, the worst day in the forecast.

Measured near Seattle

Station and measurements	Distance	US AQI	Level
Seattle-10th & Weller AirNow, reference monitor PM_2.5: 17 µg/m³ · Fri 8:00 AM NO₂: 52 µg/m³ · Fri 8:00 AM CO: 687 µg/m³ · Fri 8:00 AM	1.4 km	66	Moderate
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 21 µg/m³ · Fri 9:00 AM	1.4 km	73	Moderate
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 22 µg/m³ · Fri 9:00 AM	1.9 km	75	Moderate

Air quality near Seattle

US AQI right now. Cleanest nearby: Sacramento (29); worst: Vancouver (83). The tick on each bar is Seattle, at 62.

Vancouver 195 km N 83 Moderate
Portland 234 km S 71 Moderate
Calgary 710 km NE 66 Moderate
Edmonton 907 km NE 62 Moderate
Sacramento 1,006 km S 29 Good
San Francisco 1,093 km S 41 Good

All 162 cities →

About this forecast

Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (about 10 km inside Europe). Global runs update every 12 hours and European runs every 24 hours. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown. Nearby station measurements are independent observations, not adjustments to the forecast. The point forecast uses Open-Meteo’s CAMS products, including a separate carbon monoxide product; it can differ from the globe’s global grid. The AQI rates each hour on the US EPA scale, the same way the map colors it; official daily figures average over 24 hours (8 for ozone), so they can read lower after a short peak. Readings for 47.61°N, 122.33°W, valid 2026-11-13 17:00 UTC.