SmogRank / Japan / Nagano / Hakuba

Hakuba, month by month

Hakuba has a measured daily mean on 261 days since 24 August 2023. Its worst month was May 2026, at 57 US AQI (12.3 µg/m³), 556th of 2,874 cities on that month's world ranking. Its cleanest was September 2026, at 16 US AQI (2.9 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)193 days measured
JannoneFebnoneMar5 daysApr55#762May57#556Jun45#1,039Jul57#884Aug47#1,422Sep16#2,926Oct29#2,162
2025too few days for a mean (a year needs 256)0 days measured
JannoneFebnoneMarnoneAprnoneMaynoneJunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
2024too few days for a mean (a year needs 257)14 days measured
JannoneFeb5 daysMar9 daysAprnoneMaynoneJunnoneJulnoneAugnoneSepnoneOctnoneNovnoneDecnone
2023too few days for a mean (a year needs 256)54 days measured
JanFebMarAprMayJunJulAug2 daysSep13 daysOct13 daysNov16 daysDec10 days
Each square is a month's mean PM2.5 in US AQI from Hakuba's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Hakuba marked; each year, the year's. A dashed square is the running month, so far.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

32 months
MonthWhy
Mar 20265 of 31 days measured; a month needs 22. The others: 1 with readings for part of the day (a day needs 18 hours), 25 with under 18 hours of readings or readings that failed our checks.
Feb 2026No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks.
Jan 2026No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks.
Dec 2025No day measured.
Nov 2025No day measured.
Oct 2025No day measured.
Sep 2025No day measured.
Aug 2025No day measured.
Jul 2025No day measured.
Jun 2025No day measured.
May 2025No day measured.
Apr 2025No day measured.
Mar 2025No day measured.
Feb 2025No day measured.
Jan 2025No day measured.
Dec 2024No day measured. The others: 31 with no readings from the monitor.
Nov 2024No day measured. The others: 22 with no readings from the monitor, 8 with readings for part of the day (a day needs 18 hours).
Oct 2024No day measured. The others: 17 with no readings from the monitor, 14 with readings for part of the day (a day needs 18 hours).
Sep 2024No day measured. The others: 27 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours).
Aug 2024No day measured. The others: 30 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours).
Jul 2024No day measured. The others: 23 with no readings from the monitor, 8 with readings for part of the day (a day needs 18 hours).
Jun 2024No day measured. The others: 30 with no readings from the monitor.
May 2024No day measured. The others: 31 with no readings from the monitor.
Apr 2024No day measured. The others: 30 with no readings from the monitor.
Mar 20249 of 31 days measured; a month needs 22. The others: 18 with no readings from the monitor, 2 with readings for part of the day (a day needs 18 hours), 1 with readings left out by our checks, 1 missing from OpenAQ's archive.
Feb 20245 of 29 days measured; a month needs 21. The others: 5 with no readings from the monitor, 6 with readings for part of the day (a day needs 18 hours), 12 with readings left out by our checks, 1 missing from OpenAQ's archive.
Jan 2024No day measured. The others: 15 with no readings from the monitor, 5 with readings for part of the day (a day needs 18 hours), 11 with readings left out by our checks.
Dec 202310 of 31 days measured; a month needs 22. The others: 5 with no readings from the monitor, 16 with readings for part of the day (a day needs 18 hours).
Nov 202316 of 30 days measured; a month needs 21. The others: 3 with no readings from the monitor, 11 with readings for part of the day (a day needs 18 hours).
Oct 202313 of 31 days measured; a month needs 22. The others: 14 with no readings from the monitor, 4 with readings for part of the day (a day needs 18 hours).
Sep 202313 of 30 days measured; a month needs 21. The others: 13 with no readings from the monitor, 4 with readings for part of the day (a day needs 18 hours).
Aug 20232 of 31 days measured; a month needs 22. The others: 5 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours).

A day counts once 18 hours of it are measured; a month needs 70% of its days.

Hakuba's worst months

MonthUS AQIDays measuredWorld rank
May 2026 5712.3 µg/m³31 of 31556thof 2,874
July 2026 5712.1 µg/m³29 of 31884thof 2,784
April 2026 5511.5 µg/m³30 of 30762ndof 2,941
August 2026 478.4 µg/m³31 of 311,422ndof 2,896
June 2026 458.1 µg/m³30 of 301,039thof 2,497
September 2026 162.9 µg/m³27 of 302,926thof 2,981

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.

Hakuba's worst days

DayUS AQIEpisode
29 Mar 2026 11139.5 µg/m³Japan and South Korea, March 2026
28 Mar 2026 9934.9 µg/m³Japan and South Korea, March 2026
30 Mar 2026 9231.0 µg/m³Japan and South Korea, March 2026
10 Jul 2026 8326.5 µg/m³–
20 May 2026 8225.9 µg/m³–
11 Jul 2026 8225.6 µg/m³–
19 May 2026 8024.5 µg/m³–
21 Jul 2026 8024.5 µg/m³–
22 Jul 2026 7924.1 µg/m³–
2 May 2026 7522.1 µg/m³–

Daily means, the highest since 24 Aug 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, Hakuba, Japan, 24 Aug 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/hakuba/history (accessed 12 Oct 2026).

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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.

Hakuba 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).