McAllen Air Quality in May

Across 2019–2025, McAllen's May air quality had a median AQI of 59 (Moderate) over 217 monitored days in the McAllen-Edinburg-Mission, TX area. 9.6% of May days (21 of 217) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 82.9% of days. The cleanest May on record here was 2020 (median AQI 46, 0 days above 100) and the worst was 2024 (median 105, 18 days above 100, peak AQI 153).

59
Median AQI
Moderate
9.6%
Days above AQI 100
21 of 217 days
97
90th percentile AQI
worst 1 day in 10
153
Peak AQI
Unhealthy
PM2.5
Main pollutant
82.9% of days
30.9%
Good days
67 of 217
  • Good: 30.9%
  • Moderate: 59.4%
  • Unhealthy for Sensitive Groups: 7.8%
  • Unhealthy or worse: 1.8%

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QUICK ANSWER

How is the air in McAllen in May?

Moderate on a typical day: median AQI 59 across 2019–2025, with 9.6% of May days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 30.9% of May days were Good (AQI 0–50), 59.4% Moderate (51–100).
  • 21 days of 217 reached AQI 101+; the May peak was 153.
  • Best May: 2020; worst May: 2024.

Frequently asked questions

What is the air quality like in McAllen in May?

Across 2019–2025, the median daily AQI in McAllen in May was 59 (Moderate). 30.9% of days were Good, 59.4% Moderate, and 9.6% 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 McAllen?

A typical May day in McAllen is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 10 of May days (9.6%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

Which pollutant causes McAllen's May air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 82.9% of May days in McAllen. The highest May AQI recorded in 2019–2025 was 153 (Unhealthy), in 2024.

McAllen May air quality, year by year

McAllen May air quality by year (McAllen-Edinburg-Mission, TX, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
201931632106PM2.5
2020cleanest3146071PM2.5
20213153081PM2.5
20223161090PM2.5
20233147095PM2.5
2024worst3110518153PM2.5
202531631101PM2.5

What May air means in McAllen

A typical May day in McAllen is Moderate (median AQI 59): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 10 of May days (9.6%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.

May's median AQI of 59 is above McAllen's whole-year median of 50, making it one of the area's dirtier periods. Nationally, the median May AQI across every EPA metro area (104,064 metro-days, 2019–2025) is 44, so McAllen runs above the national May norm; 9.6% of its May days topped AQI 100 versus 1.3% nationally (above average).

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

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

Right now in McAllen

The latest EPA AirNow observation puts McAllen's AQI at 47 (PM2.5). The figures above are multi-year month statistics, not today's reading.

View current McAllen air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (McAllen-Edinburg-Mission, TX), 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.