SmogRank / United States / Idaho / Boise
Boise, month by month
Boise has a measured daily mean on 455 days since 16 January 2023. Its worst month was July 2026, at 81 US AQI (25.0 µg/m³), 219th of 2,784 cities on that month's world ranking. Its cleanest was April 2026, at 16 US AQI (2.9 µg/m³).
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
30 months
| Month | Why |
|---|---|
| Jun 2025 | 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 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Dec 2024 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Nov 2024 | No day measured. The others: 30 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 | No day measured. The others: 30 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 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | No day measured. The others: 1 missing from OpenAQ's archive, 30 with under 18 hours of readings or readings that failed our checks. |
| Feb 2024 | No day measured. The others: 1 missing from OpenAQ's archive, 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2024 | No day measured. The others: 31 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 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | No day measured. The others: 30 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 | No day measured. The others: 30 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 | No day measured. The others: 3 missing from OpenAQ's archive, 27 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | No day measured. The others: 20 missing from OpenAQ's archive, 11 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | No day measured. The others: 25 missing from OpenAQ's archive, 3 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 1 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 14 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.
Boise's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 8125.0 µg/m³ | 219thof 2,784 | North-western United States and Canada, July and August 2026 |
| August 2026 | 7723.1 µg/m³ | 192ndof 2,896 | North-western United States and Canada, 4 to 22 August 2026 North-western United States and Canada, July and August 2026 |
| January 2026 | 529.6 µg/m³ | 1,149thof 2,617 | – |
| September 2025 | 437.7 µg/m³ | 1,388thof 3,104 | North-western United States and Canada, August and September 2025 |
| August 2025 | 397.1 µg/m³ | 2,132ndof 2,901 | North-western United States and Canada, August and September 2025 |
| July 2025 | 376.7 µg/m³ | 2,072ndof 2,889 | – |
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.
Boise's worst days
Daily means, the highest since 16 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, Boise, United States, 16 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/boise/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.
Boise 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).