Skip to content
Park Crowd Calendar

Data sources

Every number on Park Crowd Calendartraces back to a public, authoritative dataset. We don't estimate or invent figures. Here is each source we use, what it covers, how current it is, and how often we refresh it. To understand how these inputs become a 1–10 crowd score, see our methodology.

NPS Visitor Use Statistics

The backbone of our crowd scores: official monthly recreation visits for every National Park Service unit, published through the NPS Integrated Resource Management Applications (IRMA) portal.

  • Coverage: monthly counts back several decades, per unit.
  • Vintage: we use the most recent three full calendar years.
  • Refresh cadence: re-ingested when NPS finalizes a new year of data (typically each winter/spring), which rolls the three-year window forward.
  • Source: irma.nps.gov/Stats

NOAA NCEI Climate Normals (1991–2020)

The average high, average low, and precipitation figures shown for each month are 30-year climate normals from NOAA's National Centers for Environmental Information, matched to a nearby weather station for each park.

  • Coverage: monthly normals derived from the 1991–2020 reference period.
  • Vintage: these are long-run averages, not a forecast; the set updates roughly once a decade (next release rolls to 2001–2030).
  • Source: NOAA U.S. Climate Normals

NPS Data API

Park details (fees, operating hours, official links) and current alerts — road closures, construction, and safety notices — come from the official NPS Data API.

  • Coverage: park metadata plus live alerts across NPS units.
  • Refresh cadence: alerts are refreshed daily; park fees and hours periodically.
  • Source: NPS Data API

Open-Meteo

Where we show a live 7-day forecast for the current month, it comes from Open-Meteo's free weather API.

  • Coverage: a 7-day outlook for the park's coordinates.
  • Refresh cadence: roughly every six hours.
  • Source: open-meteo.com

Park Crowd Calendar is not affiliated with the National Park Service, NOAA, or Open-Meteo. Federal data is used under the terms of the relevant agency; always verify current conditions at nps.gov before you travel.