SmogRank / Japan / Yamanashi / Kofu
Kofu, month by month
Kofu has a measured daily mean on 1,153 days since 28 July 2023. Its worst month was August 2025, at 63 US AQI (15.4 µg/m³), 328th of 2,901 cities on that month's world ranking. Its cleanest was September 2026, at 28 US AQI (5.1 µg/m³). 2025 averaged 55 US AQI (11.2 µg/m³), against 53 US AQI (10.3 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
1 month
| Month | Why |
|---|---|
| Jul 2023 | 4 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Kofu's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2025 | 6315.4 µg/m³ | 328thof 2,901 | Japan, 4 to 5 August 2025 |
| July 2026 | 6114.5 µg/m³ | 551stof 2,784 | Japan and South Korea, July 2026 |
| July 2025 | 6114.3 µg/m³ | 469thof 2,889 | Japan and South Korea, June and July 2025 |
| July 2024 | 6013.7 µg/m³ | 243rdof 2,566 | – |
| June 2025 | 5913.6 µg/m³ | 588thof 2,508 | Japan and South Korea, June and July 2025 |
| June 2024 | 5812.7 µg/m³ | 301stof 2,563 | – |
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.
Kofu's worst days
| Day | US AQI | Episode |
|---|---|---|
| 26 Mar 2025 | 10135.7 µg/m³ | Japan and South Korea, March 2025 |
| 5 Aug 2025 | 9834.4 µg/m³ | Japan, 4 to 5 August 2025 |
| 9 Jul 2025 | 9331.5 µg/m³ | Japan and South Korea, June and July 2025 |
| 8 Jul 2025 | 9130.8 µg/m³ | Japan and South Korea, June and July 2025 |
| 21 May 2025 | 8728.6 µg/m³ | Japan, May 2025 |
| 23 Jul 2026 | 8728.4 µg/m³ | Japan and South Korea, July 2026 |
| 21 Dec 2025 | 8527.2 µg/m³ | Japan, December 2025 |
| 27 Mar 2025 | 8326.4 µg/m³ | Japan and South Korea, March 2025 Japan, March 2025 |
| 25 Jul 2026 | 8326.4 µg/m³ | Japan and South Korea, July 2026 |
| 6 Dec 2023 | 8225.8 µg/m³ | – |
Daily means, the highest since 28 Jul 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, Kofu, Japan, 28 Jul 2023 – 12 Oct 2026. Monitor data from Ministry of the Environment Air Pollutant Wide Area Monitoring System via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/jp/kofu/history (accessed 13 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.
Kofu now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 00:07 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).