Spokane Air Quality in May

Across 2019–2025, Spokane's May air quality had a median AQI of 42 (Good) over 217 monitored days in the Spokane-Spokane Valley, WA area. 0.0% of May days (0 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 86.2% of days. The cleanest May on record here was 2020 (median AQI 35, 0 days above 100) and the worst was 2023 (median 47, 0 days above 100, peak AQI 81).

42
Median AQI
Good
0.0%
Days above AQI 100
0 of 217 days
51
90th percentile AQI
worst 1 day in 10
81
Peak AQI
Moderate
O3
Main pollutant
86.2% of days
88.5%
Good days
192 of 217
  • Good: 88.5%
  • Moderate: 11.5%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Spokane in May?

Good on a typical day: median AQI 42 across 2019–2025, with 0.0% of May days above AQI 100. Ground-level ozone is the main driver.

  • 88.5% of May days were Good (AQI 0–50), 11.5% Moderate (51–100).
  • 0 days of 217 reached AQI 101+; the May peak was 81.
  • Best May: 2020; worst May: 2023.

Frequently asked questions

What is the air quality like in Spokane in May?

Across 2019–2025, the median daily AQI in Spokane in May was 42 (Good). 88.5% of days were Good, 11.5% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.

Is May a good time for outdoor exercise in Spokane?

A typical May day in Spokane sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.

Which pollutant causes Spokane's May air quality problems?

Ground-level ozone set the daily AQI on 86.2% of May days in Spokane. The highest May AQI recorded in 2019–2025 was 81 (Moderate), in 2023.

Spokane May air quality, year by year

Spokane May air quality by year (Spokane-Spokane Valley, WA, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20193144064O3
2020cleanest3135053O3
20213143053O3
20223138045O3
2023worst3147081O3
20243141065O3
20253144071O3

What May air means in Spokane

A typical May day in Spokane sits in the Good range (median AQI 42), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of May days reached AQI 101+ in 2019–2025.

May's median AQI of 42 is below Spokane's whole-year median of 47, making it one of the area's cleaner periods. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so Spokane runs in line with the national May norm; 0.0% of its May days topped AQI 100 versus 1.3% nationally (below average).

May is part of Spokane's spring season (March, April, May); the spring page pools all three months.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Spokane

The latest EPA AirNow observation puts Spokane's AQI at 26 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current Spokane air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Spokane-Spokane Valley, WA), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.