EnviroNearby

Weber County, Utah air quality history

Daily Air Quality Index summaries from EPA monitors in Weber, Utah, 1980–2025.

66%
Good days in 2025
45
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Weber, Utah on 365 days. 240 of those days (66%) were in the Good range, and the median daily AQI was 45. That median is about the same as the typical monitored county in Utah (median 45 across 15 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 284 days. Across the years with fuller monitoring, the share of Good days rose: an average of 47% in 1980–1982 versus 64% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 178 of 363 days1980: Moderate 165 of 363 days1980: Unhealthy for Sensitive Groups 17 of 363 days1980: Unhealthy 3 of 363 days19801981: Good 180 of 363 days1981: Moderate 167 of 363 days1981: Unhealthy for Sensitive Groups 15 of 363 days1981: Unhealthy 1 of 363 days1982: Good 157 of 365 days1982: Moderate 185 of 365 days1982: Unhealthy for Sensitive Groups 21 of 365 days1982: Very Unhealthy 2 of 365 days1983: Good 143 of 365 days1983: Moderate 204 of 365 days1983: Unhealthy for Sensitive Groups 15 of 365 days1983: Unhealthy 3 of 365 days1984: Good 142 of 366 days1984: Moderate 206 of 366 days1984: Unhealthy for Sensitive Groups 17 of 366 days1984: Unhealthy 1 of 366 days1985: Good 128 of 365 days1985: Moderate 209 of 365 days1985: Unhealthy for Sensitive Groups 23 of 365 days1985: Unhealthy 5 of 365 days19851986: Good 146 of 365 days1986: Moderate 186 of 365 days1986: Unhealthy for Sensitive Groups 32 of 365 days1986: Unhealthy 1 of 365 days1987: Good 145 of 365 days1987: Moderate 207 of 365 days1987: Unhealthy for Sensitive Groups 10 of 365 days1987: Unhealthy 3 of 365 days1988: Good 165 of 366 days1988: Moderate 181 of 366 days1988: Unhealthy for Sensitive Groups 20 of 366 days1989: Good 164 of 365 days1989: Moderate 169 of 365 days1989: Unhealthy for Sensitive Groups 30 of 365 days1989: Unhealthy 2 of 365 days1990: Good 226 of 365 days1990: Moderate 131 of 365 days1990: Unhealthy for Sensitive Groups 6 of 365 days1990: Unhealthy 2 of 365 days19901991: Good 220 of 365 days1991: Moderate 138 of 365 days1991: Unhealthy for Sensitive Groups 7 of 365 days1992: Good 216 of 366 days1992: Moderate 143 of 366 days1992: Unhealthy for Sensitive Groups 7 of 366 days1993: Good 237 of 356 days1993: Moderate 110 of 356 days1993: Unhealthy for Sensitive Groups 8 of 356 days1993: Unhealthy 1 of 356 days1994: Good 192 of 365 days1994: Moderate 148 of 365 days1994: Unhealthy for Sensitive Groups 24 of 365 days1994: Unhealthy 1 of 365 days1995: Good 226 of 365 days1995: Moderate 130 of 365 days1995: Unhealthy for Sensitive Groups 8 of 365 days1995: Unhealthy 1 of 365 days19951996: Good 190 of 366 days1996: Moderate 150 of 366 days1996: Unhealthy for Sensitive Groups 26 of 366 days1997: Good 215 of 365 days1997: Moderate 145 of 365 days1997: Unhealthy for Sensitive Groups 4 of 365 days1997: Unhealthy 1 of 365 days1998: Good 184 of 365 days1998: Moderate 149 of 365 days1998: Unhealthy for Sensitive Groups 26 of 365 days1998: Unhealthy 6 of 365 days1999: Good 147 of 365 days1999: Moderate 206 of 365 days1999: Unhealthy for Sensitive Groups 12 of 365 days2000: Good 235 of 366 days2000: Moderate 110 of 366 days2000: Unhealthy for Sensitive Groups 17 of 366 days2000: Unhealthy 4 of 366 days20002001: Good 199 of 365 days2001: Moderate 142 of 365 days2001: Unhealthy for Sensitive Groups 21 of 365 days2001: Unhealthy 3 of 365 days2002: Good 163 of 365 days2002: Moderate 167 of 365 days2002: Unhealthy for Sensitive Groups 28 of 365 days2002: Unhealthy 7 of 365 days2003: Good 191 of 365 days2003: Moderate 137 of 365 days2003: Unhealthy for Sensitive Groups 35 of 365 days2003: Unhealthy 2 of 365 days2004: Good 196 of 366 days2004: Moderate 157 of 366 days2004: Unhealthy for Sensitive Groups 10 of 366 days2004: Unhealthy 3 of 366 days2005: Good 230 of 365 days2005: Moderate 111 of 365 days2005: Unhealthy for Sensitive Groups 21 of 365 days2005: Unhealthy 3 of 365 days20052006: Good 156 of 365 days2006: Moderate 177 of 365 days2006: Unhealthy for Sensitive Groups 31 of 365 days2006: Unhealthy 1 of 365 days2007: Good 121 of 365 days2007: Moderate 203 of 365 days2007: Unhealthy for Sensitive Groups 33 of 365 days2007: Unhealthy 8 of 365 days2008: Good 107 of 366 days2008: Moderate 240 of 366 days2008: Unhealthy for Sensitive Groups 19 of 366 days2009: Good 102 of 365 days2009: Moderate 247 of 365 days2009: Unhealthy for Sensitive Groups 15 of 365 days2009: Unhealthy 1 of 365 days2010: Good 134 of 365 days2010: Moderate 207 of 365 days2010: Unhealthy for Sensitive Groups 22 of 365 days2010: Unhealthy 2 of 365 days20102011: Good 172 of 365 days2011: Moderate 171 of 365 days2011: Unhealthy for Sensitive Groups 18 of 365 days2011: Unhealthy 4 of 365 days2012: Good 139 of 366 days2012: Moderate 205 of 366 days2012: Unhealthy for Sensitive Groups 21 of 366 days2012: Unhealthy 1 of 366 days2013: Good 106 of 365 days2013: Moderate 219 of 365 days2013: Unhealthy for Sensitive Groups 35 of 365 days2013: Unhealthy 5 of 365 days2014: Good 172 of 365 days2014: Moderate 184 of 365 days2014: Unhealthy for Sensitive Groups 7 of 365 days2014: Unhealthy 2 of 365 days2015: Good 197 of 365 days2015: Moderate 155 of 365 days2015: Unhealthy for Sensitive Groups 12 of 365 days2015: Unhealthy 1 of 365 days20152016: Good 207 of 366 days2016: Moderate 139 of 366 days2016: Unhealthy for Sensitive Groups 20 of 366 days2017: Good 175 of 365 days2017: Moderate 167 of 365 days2017: Unhealthy for Sensitive Groups 21 of 365 days2017: Unhealthy 2 of 365 days2018: Good 181 of 365 days2018: Moderate 167 of 365 days2018: Unhealthy for Sensitive Groups 15 of 365 days2018: Unhealthy 2 of 365 days2019: Good 224 of 308 days2019: Moderate 82 of 308 days2019: Unhealthy for Sensitive Groups 2 of 308 days2020: Good 228 of 366 days2020: Moderate 132 of 366 days2020: Unhealthy for Sensitive Groups 6 of 366 days20202021: Good 221 of 364 days2021: Moderate 126 of 364 days2021: Unhealthy for Sensitive Groups 17 of 364 days2022: Good 205 of 365 days2022: Moderate 155 of 365 days2022: Unhealthy for Sensitive Groups 5 of 365 days2023: Good 218 of 365 days2023: Moderate 141 of 365 days2023: Unhealthy for Sensitive Groups 6 of 365 days2024: Good 243 of 366 days2024: Moderate 117 of 366 days2024: Unhealthy for Sensitive Groups 6 of 366 days2025: Good 240 of 365 days2025: Moderate 123 of 365 days2025: Unhealthy for Sensitive Groups 2 of 365 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001501980: 90th percentile AQI 931981: 90th percentile AQI 891982: 90th percentile AQI 861983: 90th percentile AQI 871984: 90th percentile AQI 911985: 90th percentile AQI 1001986: 90th percentile AQI 1001987: 90th percentile AQI 841988: 90th percentile AQI 891989: 90th percentile AQI 971990: 90th percentile AQI 721991: 90th percentile AQI 771992: 90th percentile AQI 741993: 90th percentile AQI 741994: 90th percentile AQI 931995: 90th percentile AQI 741996: 90th percentile AQI 951997: 90th percentile AQI 711998: 90th percentile AQI 971999: 90th percentile AQI 812000: 90th percentile AQI 852001: 90th percentile AQI 902002: 90th percentile AQI 1002003: 90th percentile AQI 1012004: 90th percentile AQI 842005: 90th percentile AQI 872006: 90th percentile AQI 972007: 90th percentile AQI 1052008: 90th percentile AQI 902009: 90th percentile AQI 902010: 90th percentile AQI 872011: 90th percentile AQI 902012: 90th percentile AQI 902013: 90th percentile AQI 1052014: 90th percentile AQI 802015: 90th percentile AQI 802016: 90th percentile AQI 842017: 90th percentile AQI 902018: 90th percentile AQI 902019: 90th percentile AQI 662020: 90th percentile AQI 742021: 90th percentile AQI 832022: 90th percentile AQI 742023: 90th percentile AQI 742024: 90th percentile AQI 772025: 90th percentile AQI 741980: Median AQI 511981: Median AQI 511982: Median AQI 541983: Median AQI 571984: Median AQI 561985: Median AQI 571986: Median AQI 571987: Median AQI 561988: Median AQI 541989: Median AQI 541990: Median AQI 481991: Median AQI 461992: Median AQI 481993: Median AQI 461994: Median AQI 501995: Median AQI 471996: Median AQI 501997: Median AQI 481998: Median AQI 501999: Median AQI 532000: Median AQI 442001: Median AQI 492002: Median AQI 522003: Median AQI 492004: Median AQI 492005: Median AQI 472006: Median AQI 542007: Median AQI 582008: Median AQI 562009: Median AQI 572010: Median AQI 542011: Median AQI 512012: Median AQI 542013: Median AQI 572014: Median AQI 522015: Median AQI 502016: Median AQI 492017: Median AQI 512018: Median AQI 512019: Median AQI 442020: Median AQI 452021: Median AQI 462022: Median AQI 482023: Median AQI 472024: Median AQI 452025: Median AQI 451980198519901995200020052010201520202025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Ozone28478%
Fine particles (PM2.5)6016%
Nitrogen dioxide (NO₂)164%
Coarse particles (PM10)51%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536524012320004574119Ozone
202436624311760004577122Ozone
202336521814160004774141Ozone
202236520515550004874121Ozone
2021364221126170004683140Ozone
202036622813260004574140Ozone
20193082248220004466108Ozone
2018365181167152005190159Ozone
2017365175167212005190166Ozone
2016366207139200004984143Ozone
2015365197155121005080189Ozone
201436517218472005280180PM2.5
20133651062193550057105166PM2.5
2012366139205211005490167PM2.5
2011365172171184005190160Ozone
2010365134207222005487165PM2.5
2009365102247151005790153PM2.5
2008366107240190005690136PM2.5
20073651212033380058105174PM2.5
2006365156177311005497164Ozone
2005365230111213004787159NO2
2004366196157103004984164NO2
20033651911373520049101166NO2
20023651631672870052100188NO2
2001365199142213004990161Ozone
2000366235110174004485190CO
1999365147206120005381150NO2
1998365184149266005097179Ozone
199736521514541004871159Ozone
1996366190150260005095150NO2
199536522613081004774151NO2
1994365192148241005093164NO2
199335623711081004674161Ozone
199236621614370004874114Ozone
199136522013870004677122CO
199036522613162004872183CO
1989365164169302005497159NO2
1988366165181200005489143NO2
1987365145207103005684174Ozone
19863651461863210057100169CO
19853651282092350057100192CO
1984366142206171005691154CO
1983365143204153005787185CO
1982365157185210205486207Ozone
1981363180167151005189154Ozone
1980363178165173005193182Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Utah with a similar median AQI in 2025

All monitored counties in Utah

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem