What is the air quality trend in Helena?

Over the past 14 days, Helena had an average AQI of 39 based on station measurements. The worst day was 2026-07-17 with AQI 66.

How is Helena air quality measured?

Air quality in Helena is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Helena, United States

Name: Helena Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Helena, United States.

Current AQI
Good Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

299h

PM2.5 Station

299h · 3 stations

Temperature GFS model

56pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-07-21	45	21–80	11.8 µg/m³	15h	3
2026-07-20	43	15–93	11.9 µg/m³	18h	2
2026-07-19	51	23–152	14.2 µg/m³	19h	3
2026-07-18	48	22–152	14.0 µg/m³	19h	3
2026-07-17	66	33–186	25.1 µg/m³	23h	3
2026-07-16	49	27–178	15.3 µg/m³	23h	3
2026-07-15	33	15–81	8.3 µg/m³	23h	3
2026-07-14	30	20–53	7.1 µg/m³	22h	3
2026-07-13	25	10–40	6.0 µg/m³	21h	3
2026-07-12	30	20–42	7.3 µg/m³	22h	3
2026-07-11	28	14–38	6.8 µg/m³	24h	3
2026-07-10	30	18–37	7.3 µg/m³	23h	3
2026-07-09	35	29–43	8.5 µg/m³	23h	3
2026-07-08	35	25–49	8.4 µg/m³	24h	3

Back to Helena Air Quality