SmogRank / United States / California / Calexico
Calexico, month by month
Calexico has a measured daily mean on 1,281 days since 1 January 2023. Its worst month was December 2025, at 63 US AQI (15.7 µg/m³), 696th of 3,006 cities on that month's world ranking. Its cleanest was March 2024, at 30 US AQI (5.4 µg/m³). 2025 averaged 53 US AQI (10.0 µg/m³), against 52 US AQI (9.6 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
3 months
| Month | Why |
|---|---|
| Nov 2025 | 15 of 30 days measured; a month needs 21. The others: 15 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | 14 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| Dec 2023 | 16 of 31 days measured; a month needs 22. The others: 15 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.
Calexico's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2025 | 6315.7 µg/m³ | 696thof 3,006 | Western United States and Mexico, December 2025 |
| January 2024 | 6315.6 µg/m³ | 428thof 2,385 | California and Nevada, United States, January 2024 |
| January 2025 | 5913.3 µg/m³ | 590thof 2,474 | South-western United States and Mexico, December 2024 to January 2025 |
| February 2026 | 5813.0 µg/m³ | 921stof 2,866 | – |
| November 2024 | 5812.9 µg/m³ | 515thof 2,624 | – |
| January 2023 | 5812.8 µg/m³ | 317thof 1,261 | – |
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.
Calexico's worst days
| Day | US AQI | Episode |
|---|---|---|
| 17 Dec 2025 | 14653.8 µg/m³ | Western United States and Mexico, December 2025 |
| 26 Nov 2024 | 13248.2 µg/m³ | – |
| 19 Jun 2025 | 12444.7 µg/m³ | – |
| 12 Jan 2024 | 12344.3 µg/m³ | – |
| 31 Dec 2024 | 12244.1 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
| 23 Nov 2024 | 10838.5 µg/m³ | – |
| 24 Dec 2023 | 10838.2 µg/m³ | Western United States and Mexico, December 2023 |
| 1 Jan 2025 | 10537.0 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
| 23 Dec 2025 | 10336.5 µg/m³ | – |
| 17 Jan 2024 | 10336.2 µg/m³ | California and Nevada, United States, January 2024 |
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, Calexico, United States, 1 Jan 2023 – 10 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/calexico/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.
Calexico now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 18:07 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).