Utah · County air quality · 2025

Weber County, Utah

Median AQI 45 (Good). 65.8% of monitored days rated Good, direct from EPA Air Quality System stations.

45
Median AQI
65.8%
Good-air days
0
Unhealthy days
24%
Cleaner than US counties

Weber County's 2025 annual median AQI is 45 (Good), with 65.8% Good days

According to the U.S. EPA Air Quality System, Weber County, Utah posted a 2025 median AQI of 45 (Good) across 365 monitored days, with 65.8% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.

Data source EPA Air Quality System (AQS)

Cleaner than US
Weber County's 65.8% Good-day share places it cleaner than 24% of US counties in 2025.
Closest median-AQI peer
Baltimore County (64.7% Good, median AQI 45) is the closest nationwide median-AQI peer to Weber County.
2020–2025 trend
Weber County's floor-qualifying Good-day share is improving from 2020 to 2025 (62.3% → 65.8%).
Median AQI
Median AQI: 45

According to the 2025 EPA AQS county release on PlainAirData, Weber County, Utah ranks #750 of 951 by median AQI (45) and #721 by good-day share (65.8%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.

Data updated August 2026

Weber County AQI category distribution Stacked-segment bar showing the share of monitored days that fell in each EPA AQI category, Good, Moderate, USG, Unhealthy, Very Unhealthy, Hazardous, with median AQI marker. AQI category distribution 365 monitored days G M Median AQI 45 0 50 100 150 200 300 500 Weber County
  • Good · 240 d · 65.8%
  • Moderate · 123 d · 33.7%
  • USG · 2 d · 0.5%

How did Weber County's air break down in 2025?

Across 365 monitored days, 240 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 119 (USG).

EPA AQS →
Weber County, Good days share 65.8%
National avg

Share of monitored days at AQI 0-50 (Good band).

Weber County, Unhealthy-or-worse share 0.0%
National avg

Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).

Where Weber County sits nationally

COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Weber County's Good-day share is 65.8% - cleaner than 24% of that comparison set.

Weber County Good-day share vs. every US county

Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release

65.8% 24th percentile higher than 24% of 951 US counties

0.0%–5.0%: 0 US counties (0%). Below this entry. 5.0%–10.0%: 1 US counties (0%). Below this entry. 10.0%–15.0%: 4 US counties (0%). Below this entry. 15.0%–20.0%: 4 US counties (0%). Below this entry. 20.0%–25.0%: 1 US counties (0%). Below this entry. 25.0%–30.0%: 5 US counties (1%). Below this entry. 30.0%–35.0%: 9 US counties (1%). Below this entry. 35.0%–40.0%: 4 US counties (0%). Below this entry. 40.0%–45.0%: 16 US counties (2%). Below this entry. 45.0%–50.0%: 16 US counties (2%). Below this entry. 50.0%–55.0%: 32 US counties (3%). Below this entry. 55.0%–60.0%: 50 US counties (5%). Below this entry. 60.0%–65.0%: 77 US counties (8%). Below this entry. 65.0%–70.0%: 93 US counties (10%). This entry sits in this band. 70.0%–75.0%: 109 US counties (11%). Above this entry. 75.0%–80.0%: 114 US counties (12%). Above this entry. 80.0%–85.0%: 123 US counties (13%). Above this entry. 85.0%–90.0%: 99 US counties (10%). Above this entry. 90.0%–95.0%: 117 US counties (12%). Above this entry. 95.0%–100.0%: 70 US counties (7%). Above this entry. 100.0%–105.0%: 7 US counties (1%). Above this entry. This county 0.0% 100% every floor-qualified US county, bucketed by value

Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025

Pollutant Breakdown

Days where each pollutant was the primary driver of AQI readings in Weber County.

Weber County, Utah criteria pollutant distribution Stratified-band visualization showing the share of monitored days each criteria pollutant (PM2.5, PM10, O3, NO2, CO) was the primary AQI driver. Ozone · 77.8% PM2.5 · 16.4% 0% 25% 50% 75% 100% Weber County, Utah · 365 monitored days Criteria pollutant column
  • Ozone · 284 days · 77.8%
  • PM2.5 · 60 days · 16.4%
  • NO₂ · 16 days · 4.4%
  • PM10 · 5 days · 1.4%

2024 daily-monitor rhythm in Weber County

Month-by-month median AQI from EPA day-level county monitors (366 reported days in 2024). Jul posted the highest typical readings (median AQI 74, peak 112); Nov was cleanest at median 34. Summer months (Jun–Aug) averaged median AQI 59 vs 41 in Dec–Feb.

0 10 20 30 40 50 60 70 80 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 52 37 41 46 45 50 74 54 48 43 34 35
Weber County median daily AQI by calendar month (2024, EPA daily county file)

Five-year seasonal record

EPA day-level county files · 2020–2024

1,826 daily readings show a recurring local pattern: Jul has the highest matched-month median AQI (68), while Nov is lowest (36). Each cell is that month’s median daily AQI, not a current-air forecast.

JanFebMarAprMayJunJulAugSepOctNovDec
2020 373741444950586153333245
2021 513238444450807158373937
2022 594439434564616152433840
2023 344644475163675845373744
2024 523741464550745448433435

Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.

Health Impact Assessment

Moderate

Weber County's air quality is rated Moderate based on 65.8% good air days. No unhealthy air days were recorded in 2025.

Air quality was acceptable on 65.8% of monitored days in 2025, with a median AQI of 45. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.

The dominant pollutant is Ozone, driving AQI on 284 of 365 monitored days.

5-Year Air Quality Trend

Air quality is improving in Weber County. Highest Good-day share: 2024 (66.4%, 243 of 366 monitored days).

Year Good Moderate USG Unhealthy Median AQI
2020 228 132 6 0 45
2021 221 126 17 0 46
2022 205 155 5 0 48
2023 218 141 6 0 47
2024 243 117 6 0 45
2025 240 123 2 0 45

How does Weber County compare?

How Weber County compares

Good-day share worse than typical
Weber County 65.8%
Baltimore County, Maryland 64.7%
Typical US county 76.0%
Median AQI worse than typical
Weber County 45
Baltimore County, Maryland 45
Typical US county 39
Unhealthy days / yr better than typical
Weber County 0
Baltimore County, Maryland 0
Typical US county 1

Data Sources

Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.

Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.

Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Weber County, Utah · 2020–2025

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Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.