High and low tide predictions for a single day.

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Request parameters

Name	Type	In	Required	Description	Example
date1	Date	Body	Yes	The start date (or single query date) for the computation. Accepted formats: YYYY-MM-DD for date-only fields, ISO 8601 datetime string (YYYY-MM-DDTHH:MM) for datetime fields.
lat	Float	Body	Yes	Observer latitude in decimal degrees. Valid range: -90.0 (South Pole) to 90.0 (North Pole). Used to compute the observer's position on Earth's surface for all sky calculations.
lon	Float	Body	Yes	Observer longitude in decimal degrees. Valid range: -180.0 to 180.0. Negative values are west of the Prime Meridian, positive values are east.
cutoff_km	Float	Body	Optional
timezone_slug	Choice	Body	Optional	Slug of a timezone record used to localise event datetimes in the response (e.g. america-new-york). When omitted, the timezone is derived automatically from the supplied coordinates. Obtain valid timezone slugs from the timezone list endpoint.

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Response fields

Name	Type	Nullable	Description	Example
coastal	Boolean	—	True if the location is within the EOT20 ocean model grid and tidal data is available. False for inland, polar (beyond ±66°), or non-tidal locations. When false, events is always an empty list.	true
date	String	—	The calendar day for which tide events were computed, in YYYY-MM-DD format.	2026-05-09
events	Array	—	List of high and low tide events for the day, sorted chronologically by minute_of_day. May contain 0–4 entries depending on the tidal regime at the location.
events[].height_m	Float	—	Predicted tide height in metres above mean sea level at the time of the event.	2.87
events[].minute_of_day	Integer	—	Minutes elapsed since local midnight (0–1439). Useful for sorting or charting events on a timeline.	582
events[].time	String	—	Local time of the tide event in 12-hour format (e.g. '9:42 am'). Expressed in the resolved timezone.	9:42 am
events[].type	String	—	'High' for a high tide (local maximum) or 'Low' for a low tide (local minimum).	High
lat	Float	—	Observer latitude in decimal degrees as supplied in the request.	48.4359
lon	Float	—	Observer longitude in decimal degrees as supplied in the request.	-123.35155
tz	String	—	IANA timezone name resolved for the observer coordinates, or the value derived from timezone_slug if supplied.	America/Vancouver