Air Quality
Wyoming enjoys some of the cleanest air in the country, with low population density and open landscapes limiting pollution.
Monitored days with good air quality
1990–2025U.S. EPA AirData, Annual AQI by County, all monitored Wyoming counties.
Monitored days unhealthy for sensitive groups or worse
1990–2025U.S. EPA AirData, Annual AQI by County (AQI above 100).
| Indicator | Wyoming | U.S. |
|---|---|---|
| Average PM2.5 (µg/m³) | 4.5 | 7.5 |
- •Wyoming's vast open spaces and small population keep air pollution levels low.
- •Occasional wildfire smoke from nearby states can temporarily degrade air quality.
- •Yellowstone and Grand Teton National Parks report some of the cleanest air readings in the U.S.
Wildfires
Wildfires are a recurring seasonal threat across Wyoming's federal rangelands and forests, especially during dry summer months.
| Indicator | Wyoming | U.S. |
|---|---|---|
| Federal land share (%) | 48 | 28 |
- •Nearly half of Wyoming's land is federally managed, much of it fire-prone forest and rangeland.
- •The 1988 Yellowstone fires remain one of the most significant wildfire events in U.S. history.
- •Dry, windy summers increase wildfire risk across Wyoming's grasslands and forests.
Drought
Parts of Wyoming, particularly the Colorado and Green River basins, face recurring and sometimes severe drought conditions.
Area in drought (D1–D4), yearly average
2000–2025U.S. Drought Monitor (NDMC / USDA / NOAA), average of weekly maps.
Area in extreme or exceptional drought (D3–D4)
2000–2025U.S. Drought Monitor (NDMC / USDA / NOAA), average of weekly maps.
| Indicator | Wyoming | U.S. |
|---|---|---|
| Share of state in drought (avg %) | 35 | 25 |
- •Snowpack levels in Wyoming's mountains directly affect Colorado River flows downstream.
- •Ranchers and farmers in Wyoming are heavily affected by multi-year drought cycles.
- •Reservoirs like Flaming Gorge help buffer Wyoming's water supply during dry years.
Water Usage
Water in Wyoming is dominated by agricultural irrigation, with the state serving as a headwaters source for major Western river systems.
| Indicator | Wyoming | U.S. |
|---|---|---|
| Agricultural share of water use (%) | 85 | 40 |
- •Wyoming is a headwaters state, feeding the Colorado, Missouri, and Columbia river systems.
- •Irrigation for agriculture accounts for the large majority of the state's water withdrawals.
- •Interstate water compacts govern much of Wyoming's river allocations to downstream states.
Emissions
Wyoming has the highest per-capita CO2 emissions in the United States, driven by its coal mining and power generation industries.
Energy-related CO₂ emissions
1970–2021U.S. EIA State Energy Data System, all sectors and fuels (FRED EMISSCO2TOTVTTTOWYA).
Transportation CO₂ emissions
1970–2021U.S. EIA State Energy Data System, transportation sector (FRED EMISSCO2TOTVTCTOWYA).
| Indicator | Wyoming | U.S. |
|---|---|---|
| CO2 emissions per capita (metric tons) | 100 | 15 |
- •Wyoming's coal mining and export activity drive its outsized per-capita emissions.
- •Much of the energy Wyoming produces is exported and consumed in other states.
- •Wyoming is exploring carbon capture projects tied to its coal and gas industries.
Climate Indicators
Wyoming's high-elevation, semi-arid climate features cold winters, warm summers, and increasing variability in precipitation.
Average annual temperature
1895–2025NOAA National Centers for Environmental Information, Climate at a Glance, statewide January–December average.
Annual precipitation
1895–2025NOAA National Centers for Environmental Information, Climate at a Glance, statewide January–December total.
| Indicator | Wyoming | U.S. |
|---|---|---|
| Mean elevation (m) | 2040 | 760 |
- •Wyoming has the second-highest mean elevation of any U.S. state.
- •Gannett Peak, at 4,209 m, is Wyoming's highest point.
- •Recurring drought conditions affect the Colorado and Green River basins in the state.