SmogRank / United States / Arizona / Casa Grande
Casa Grande, month by month
Casa Grande has a measured daily mean on 1,229 days since 1 January 2023. Its worst month was December 2024, at 59 US AQI (13.6 µg/m³), 551st of 2,616 cities on that month's world ranking. Its cleanest was March 2023, at 19 US AQI (3.4 µg/m³). 2025 averaged 44 US AQI (7.9 µg/m³), against 48 US AQI (8.6 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
7 months
| Month | Why |
|---|---|
| Jan 2026 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Dec 2025 | 16 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Nov 2025 | 9 of 30 days measured; a month needs 21. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 18 of 30 days measured; a month needs 21. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 12 of 28 days measured; a month needs 20. The others: 14 missing from OpenAQ's archive, 2 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Casa Grande's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2024 | 5913.6 µg/m³ | 551stof 2,616 | South-western United States and Mexico, December 2024 to January 2025 |
| August 2026 | 5813.1 µg/m³ | 483rdof 2,896 | – |
| January 2025 | 5611.7 µg/m³ | 753rdof 2,474 | South-western United States and Mexico, December 2024 to January 2025 |
| October 2024 | 5611.6 µg/m³ | 414thof 2,020 | – |
| August 2025 | 5410.9 µg/m³ | 1,027thof 2,901 | – |
| November 2024 | 5410.5 µg/m³ | 764thof 2,624 | – |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Casa Grande's worst days
| Day | US AQI | Episode |
|---|---|---|
| 3 Aug 2026 | 13448.8 µg/m³ | – |
| 8 Jan 2025 | 9834.4 µg/m³ | – |
| 25 Aug 2025 | 9633.0 µg/m³ | – |
| 21 Aug 2025 | 9432.3 µg/m³ | – |
| 28 Mar 2026 | 9030.2 µg/m³ | – |
| 1 Jan 2025 | 8929.5 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
| 31 Dec 2024 | 8828.7 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
| 9 Aug 2026 | 8627.9 µg/m³ | – |
| 19 Aug 2026 | 8627.7 µg/m³ | – |
| 6 Aug 2026 | 8426.7 µg/m³ | – |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Casa Grande, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/casa-grande/history (accessed 12 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Casa Grande now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 20:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).