SmogRank / Peru / Callao / Callao
Callao, month by month
Callao has a measured daily mean on 942 days since 1 January 2023. Its worst month was May 2025, at 99 US AQI (34.6 µg/m³), 109th of 2,826 cities on that month's world ranking. Its cleanest was February 2024, at 49 US AQI (8.8 µg/m³). 2025 averaged 77 US AQI (23.1 µg/m³), against 71 US AQI (20.1 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
18 months
| Month | Why |
|---|---|
| Oct 2026 | 4 of 11 days measured; a month needs 8. The others: 7 with readings for part of the day (a day needs 18 hours). |
| Sep 2026 | 7 of 30 days measured; a month needs 21. The others: 1 with no readings from the monitor, 22 with readings for part of the day (a day needs 18 hours). |
| Aug 2026 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | 9 of 31 days measured; a month needs 22. The others: 22 with under 18 hours of readings or readings that failed our checks. |
| Sep 2024 | 20 of 30 days measured; a month needs 21. The others: 10 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 19 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks. |
| Dec 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Nov 2023 | 4 of 30 days measured; a month needs 21. The others: 26 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | 5 of 30 days measured; a month needs 21. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | No day measured. The others: 1 missing from OpenAQ's archive, 30 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 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 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Apr 2023 | 14 of 30 days measured; a month needs 21. The others: 3 missing from OpenAQ's archive, 13 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 8 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive, 3 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
| Jan 2023 | 20 of 31 days measured; a month needs 22. The others: 7 missing from OpenAQ's archive, 4 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.
Callao's worst months
| Month | US AQI | World rank |
|---|---|---|
| May 2025 | 9934.6 µg/m³ | 109thof 2,826 |
| June 2024 | 9231.1 µg/m³ | 44thof 2,563 |
| January 2024 | 8929.7 µg/m³ | 120thof 2,385 |
| April 2025 | 8929.7 µg/m³ | 175thof 2,951 |
| July 2025 | 8828.8 µg/m³ | 93rdof 2,889 |
| July 2024 | 8728.4 µg/m³ | 63rdof 2,566 |
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.
Callao's worst days
| Day | US AQI |
|---|---|
| 10 May 2025 | 15560.9 µg/m³ |
| 27 Jun 2024 | 15257.0 µg/m³ |
| 4 Jul 2025 | 14252.3 µg/m³ |
| 18 May 2025 | 13750.2 µg/m³ |
| 19 Mar 2024 | 13449.1 µg/m³ |
| 14 May 2025 | 13448.8 µg/m³ |
| 21 Jun 2024 | 13348.3 µg/m³ |
| 16 May 2025 | 13248.0 µg/m³ |
| 3 Jul 2025 | 13147.8 µg/m³ |
| 20 Jun 2024 | 13147.7 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, Callao, Peru, 1 Jan 2023 – 10 Oct 2026. Monitor data from Senamhi via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/pe/callao/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.
Callao now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 21:07 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).