Data sources

Every number on this site comes from a U.S. government source. Federal data is in the public domain; we cache it, send each request with our application name, and show the station and reading time.

Tides

NOAA Center for Operational Oceanographic Products and Services (CO-OPS): high and low tide predictions for 3,500 stations, fetched a year per station through the CO-OPS data API, in feet above mean lower low water (MLLW). Harmonic stations have their own predictions; subordinate stations are NOAA’s predictions for a reference station corrected by fixed time and height differences.

The curve between each high and low is drawn with the standard cosine shape. Real tides can differ from it, especially in rivers and inlets.

Which station for which town

Towns and beaches come from the USGS Geographic Names Information System (GNIS). Each is matched to NOAA prediction stations within 10 miles. Among those close to the nearest one, a station on the open coast (a beach, pier or inlet) is preferred to one up a creek, river or waterway, and a few are chosen by hand where that rule picks the wrong water. Places that share a station at about the same distance are covered by one page.

Water temperature

  • NOAA CO-OPS water temperature at 236 stations, read every hour (station list).
  • NOAA National Data Buoy Center (NDBC) buoys and coastal stations, from the latest observations file.
  • NASA JPL MUR sea-surface temperature (Multi-scale Ultra-high Resolution, 1 km, daily and monthly), through NOAA CoastWatch ERDDAP, at the nearest ocean point to each town. Monthly averages cover 2016–2025.

A sensor reading is hidden after 12 hours without a new one.

Lake levels

  • U.S. Army Corps of Engineers, CWMS Data API (cwms-data.usace.army.mil): pool elevations and the “top of conservation” level, which is full pool, by season.
  • U.S. Geological Survey Water Services (waterservices.usgs.gov): lake elevation gauges, every 15 minutes, and daily values for the charts.

Each lake lists its feeds in order; every hour we take the one with the newest reading, because some agency series stop updating for days. Full pool for the Kansas City District lakes (Truman, Stockton, Pomme de Terre) is the published top of the multipurpose pool. A level is hidden after 36 hours without a new reading. These are provisional data and can be revised by the agency.

Sun and moon

Sunrise and sunset use NOAA’s solar calculator equations; moon phases use Jean Meeus’s Astronomical Algorithms. Both are calculated for each town, within a minute or two.