NOAA Tides and Currents API is the authoritative source for US stations, free and well-documented. International coverage comes from per-country agencies (UK Hydrographic Office, Fisheries and Oceans Canada, BOM Australia) with varying access models. Most US-focused sites use NOAA exclusively; international expansion requires per-country source configuration.

Seven days is the standard. List mappings render each day as a repeated item with the day's high and low tides, heights, and sunrise / sunset context. Some sites extend to 14 or 30 days for paying users; the public page caps at 7 to balance content depth with predictions-table size.

NOAA's subordinate stations derive predictions from a reference station with an offset. Store the reference-station ID and the offset on each subordinate row; the predictions endpoint can compute the subordinate values directly or via NOAA's API field for subordinate output. Both approaches yield the same predictions.

Yes. Major-minor solunar periods are a function of moonrise, moonset, and noon, all computable from station coordinates. A list mapping renders the next 7 days of solunar windows alongside the tide table. Fishing-oriented sites find this combination doubles engagement compared to tides alone.

NOAA publishes predictions in MLLW (mean lower low water) by default, but tidal users sometimes need MHHW, MTL, or NAVD88 references. Add a datum column on each station and a selector mapping to surface it on the page. For paddling and surfing audiences, datum is rarely material; for navigation audiences, it's critical.

Place schema for the station with GeoCoordinates and addressRegion. A Dataset schema can describe the prediction table as a structured tide dataset. Most sites prioritize Place over Dataset because the visitor query intent is location-based. Sun-and-moon context fields enhance Place markup further.

NOAA stations include current data alongside tide data for many locations. Add columns for current speed, direction, and flood / ebb times, and render via selector or list mappings. Currents matter most for boat-launch and kayaking audiences; surfers care less. Splitting into a current-station page group keeps each surface focused.

Yes. SleekRank registers every generated URL with the sitemap and noindexes the base template page. NOAA's station roster is stable so the sitemap stays predictable. Adding international stations is purely a source-config expansion; the template handles new stations without modification.