Credits

COWX (COlorado + Weather) aggregates publicly available weather, air quality, agricultural, and aviation data for Colorado. This project is unofficial and is not affiliated with NOAA, the National Weather Service, EPA, CSU, PurpleAir, or any other data provider.

Why this site exists

I built COWX because I wanted hyper-focused, consolidated Colorado weather in one place — current conditions, forecasts, alerts, air quality, ag stations, aviation observations, and the links to dig deeper — without ads, clutter, or a dozen open tabs. Once it was useful for me, sharing it felt like the obvious next step: neighbors, pilots, farmers, firefighters, ham radio operators, and anyone else who needs clear local weather should be able to open a page and get the detail without fighting a feed of promotions.

Weather & forecasts

• Open-Meteo — model forecasts (current, hourly, daily) and ERA5 reanalysis climatology (1991–2020 day-of-year means for “vs typical” comparisons; not official NOAA/NCEI climate normals)
• National Weather Service / api.weather.gov — active alerts, Area Forecast Discussions (AFD), Hazardous Weather Outlooks (HWO), Fire Weather Planning Forecasts (FWF), point-forecast links

Air quality

• AirNow (EPA) — official AQI observations when configured
• PurpleAir — community PM sensors when configured
• Open-Meteo air quality — model PM / US AQI for every catalog point

Pollen & allergy (offsite)

• Pollen.com — ZIP forecast links resolved from nearest Colorado ZIP (not scraped or cached)
• AAAAI National Allergy Bureau — statewide observed pollen map / NAB overview links

Astronomy

• Local sun and moon calculations (SunCalc-style algorithms) — sunrise/sunset, twilight, moon phase and rise/set for each catalog lat/lon; no third-party astronomy API

Agriculture

• CoAgMET — Colorado State University / Colorado Climate Center research stations

Hydrology & snowpack

• USGS Water Data — real-time streamflow, gauge height, and water temperature
• Colorado Basin River Forecast Center (CBRFC) — seasonal water-supply / ESP model guidance (unregulated volume percent of average; guidance, not a day-to-day streamflow forecast)
• NRCS / SNOTEL — high-elevation snow depth and snow water equivalent

Aviation

• Aviation Weather Center — METAR and TAF products

Maps & UI

• Base map tiles: CARTO / OpenStreetMap contributors
• Optional Colorado address geocoding: Nominatim (OpenStreetMap data, ODbL) — user-submitted lookups only
• Map library: Leaflet
• Animated radar loops: RainViewer
• NOAA / NWS interactive radar: radar.weather.gov
• GOES satellite (CSU CIRA / RAMMB SLIDER): rammb-slider.cira.colostate.edu
• Weather icons: Meteocons by Bas Milius (MIT)
• Typeface: Outfit via Google Fonts
• Client IP geolocation: third-party CORS geo APIs (see How it works)

Roads & traveler information

• CDOT / COtrip cameras, traveler incidents, planned events, road conditions, and RWIS weather stations: maps.cotrip.org / data.cotrip.org — CARS Program camera API (no key); keyed COtrip JSON when COTRIP_API_KEY is configured (incidents, planned events, road conditions, weather stations); CDOT ArcGIS alerts as fallback when the keyed feed is skipped
• Municipal / county webcam portals (linked, not embedded) — e.g. City of Longmont, City of Boulder, Larimer County, City of Colorado Springs

Neighborhood weather, smoke & fire

• CWOP / APRS weather packets via aprs.me
• NOAA Hazard Mapping System (HMS) smoke: OSPO HMS
• SPC Fire Weather Outlooks: Storm Prediction Center
• Active wildfire locations (WFIGS): National Interagency Fire Center
• Satellite active-fire detections (VIIRS): NASA FIRMS / LANCE — thermal anomalies, not confirmed incidents; when redistributing, follow NASA ESDIS open-data guidance and include the FIRMS disclaimer. Optional FIRMS_MAP_KEY on the fetch job.
• County fire restriction status / links: Colorado Emergency Management and DFPC (always verify with the issuing agency)
• Avalanche forecasts (offsite links only): Colorado Avalanche Information Center (CAIC) — mountain-region locations link to CAIC; COWX does not scrape or rehost CAIC data (CAIC terms prohibit automated robots / data mining)
• NOAA Space Weather Prediction Center (Kp, F10.7 / SFI, R/S/G scales, GOES X-ray): SWPC · services.swpc.noaa.gov

Trademarks remain the property of their respective owners. Use of upstream data is subject to each provider’s terms of service and attribution requirements.

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