Data Sources

Every data point on this site comes from an authoritative public source. Here they are.

Tides & Water Temperature

Tide predictions, water temperature, and current data come from the NOAA Center for Operational Oceanographic Products and Services (CO-OPS). Data is pulled per beach from the nearest monitoring station via the public CO-OPS API.

Weather Forecasts & Alerts

Forecasts, current conditions, and active alerts come from the National Weather Service API. This is the same feed behind weather.gov.

Swim Advisories & Water Quality

Bacteria-level advisories for swimming come from the Maryland Healthy Beaches Program (a Maryland Department of the Environment effort) and from individual county health departments. Advisories are typically updated weekly during the swim season.

Sunrise & Sunset

Calculated locally using the standard NOAA solar position algorithm. No API call needed.

Beach Metadata

Static information about each beach — address, parking, amenities, dog rules, entry fees — is manually curated from official park websites, county pages, and visitor centers. If you see outdated or incorrect info, email us.

The Beach Day Score

The 0-100 score combines current water temperature, air temperature, wind speed, rain probability, active weather alerts, and swim advisories into a single rating. The formula is opinionated — it assumes you want to actually get in the water — but the underlying data is transparent and the methodology is linked from every beach page.

Update frequency

The site is statically generated and rebuilds on a scheduled cadence. Conditions you see are typically within the last hour.