SmogRank / Mexico / Baja California / Tijuana
Tijuana, month by month
Tijuana has a measured daily mean on 927 days since 1 January 2023. Its worst month was December 2025, at 143 US AQI (52.7 µg/m³), 185th of 3,006 cities on that month's world ranking. Its cleanest was July 2025, at 54 US AQI (10.9 µg/m³). 2025 averaged 73 US AQI (20.9 µg/m³), against 73 US AQI (20.9 µg/m³) in 2023.
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
16 months
| Month | Why |
|---|---|
| Dec 2024 | 12 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks. |
| Nov 2024 | 2 of 30 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Oct 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Aug 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jun 2024 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| May 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Apr 2024 | 3 of 30 days measured; a month needs 21. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 4 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | 1 of 29 days measured; a month needs 21. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 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. |
| Jun 2023 | 13 of 30 days measured; a month needs 21. The others: 17 with under 18 hours of readings or readings that failed our checks. |
| May 2023 | 21 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 1 of 28 days measured; a month needs 20. The others: 25 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.
Tijuana's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| December 2025 | 14352.7 µg/m³ | 185thof 3,006 | Western United States and Mexico, December 2025 |
| December 2023 | 10035.4 µg/m³ | 48thof 2,247 | Western United States and Mexico, December 2023 |
| January 2026 | 9331.8 µg/m³ | 158thof 2,617 | – |
| November 2025 | 9130.8 µg/m³ | 251stof 2,715 | – |
| February 2026 | 9130.5 µg/m³ | 249thof 2,866 | – |
| November 2023 | 8426.9 µg/m³ | 39thof 2,243 | – |
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.
Tijuana's worst days
| Day | US AQI | Episode |
|---|---|---|
| 21 Dec 2025 | 247172.0 µg/m³ | Western United States and Mexico, December 2025 |
| 27 Aug 2026 | 210135.0 µg/m³ | – |
| 14 Jul 2026 | 196120.0 µg/m³ | – |
| 20 Dec 2025 | 196119.0 µg/m³ | Western United States and Mexico, December 2025 |
| 10 Sept 2026 | 189110.0 µg/m³ | – |
| 6 Dec 2025 | 17690.6 µg/m³ | – |
| 25 Dec 2023 | 17082.9 µg/m³ | Western United States and Mexico, December 2023 |
| 19 Dec 2023 | 16880.1 µg/m³ | – |
| 5 Dec 2025 | 16778.8 µg/m³ | – |
| 1 Jan 2025 | 16271.7 µg/m³ | South-western United States and Mexico, December 2024 to January 2025 |
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, Tijuana, Mexico, 1 Jan 2023 – 11 Oct 2026. Monitor data from Sinaica Mexico via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/mx/tijuana/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.
Tijuana now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 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).