Data sources

Where the numbers come from

Every data point on this site comes from a free, public, authoritative source. Nothing is scraped from paywalled sources or inferred from proprietary data.

Active sources

NOAA CO-OPS (Tides & Currents)

Tide predictions (high/low times and heights) and water temperature observations at tidal stations throughout the region. Used for every tidal fishing location — Sandy Point, Point Lookout, Kent Narrows, Cape Henlopen, Kiptopeke, etc.

API reference →

National Weather Service (NWS)

Forecast conditions (air temperature, wind speed + direction, short forecast, rain probability) and active weather alerts. Used on every page.

API reference →

USGS Water Services

Water temperature and streamflow at inland gauges — Gunpowder Falls, Savage River, Youghiogheny, Monocacy, Deep Creek Lake. Used when a location is not near a NOAA CO-OPS station.

API reference →

Maryland Department of the Environment (MDE)

Swim and water-quality advisories across Maryland beaches and tidal waters. Surfaced as the "water-quality advisory" factor in the fishing-day score.

Advisory feed →

Maryland DNR, Delaware Fish & Wildlife, VMRC, VDWR, PRFC

State-agency regulation pages are the authoritative source for size limits, creel limits, season windows, and gear restrictions. Each species record in our database carries the exact URL we fetched and the date we last verified it. A quarterly automated check (npm run verify:regs) flags any page-content drift since the last verification.

Astronomical calculations

Sunrise, sunset, moon phase, moon illumination, and solunar major/minor periods are computed locally using published astronomical formulas (NOAA Solar Calculator for sun times; low-precision moon-position math for solunar). No API calls are needed for these — the math runs at build time.

What we don't do

  • We don't aggregate user-submitted catch reports.
  • We don't infer conditions at locations without a real nearby station. If a reservoir doesn't have a USGS temp gauge within range, the page shows "unavailable" — not a fabricated number.
  • We don't buy or license proprietary fishing-data feeds.
  • We don't rerank editorial content based on advertising relationships (see methodology).

Sibling site

itsabeachday.com data sources — the beach site's equivalent page, shares most of the same underlying APIs plus sea-nettle and NDBC buoy data for ocean-specific conditions.