Tides

Tide station datasets

For learners without access to tidal water, and for anyone who wants to compare coastlines that behave completely differently.

The stations

File	Station	Character	Typical range
`brest-2026-08.csv`	Brest, France	Clean semidiurnal	~6 m
`hilo-2026-08.csv`	Hilo, Hawaii	Mixed, unequal highs	~0.8 m
`fremantle-2026-08.csv`	Fremantle, Australia	Mostly diurnal	~0.6 m
`burntcoat-2026-08.csv`	Burntcoat Head, Bay of Fundy	Resonant	~16 m

Format

datetime_utc,kind,height_m
2026-08-16T05:12,high,6.42
2026-08-16T11:34,low,1.18

datetime_utc: ISO 8601, always UTC
kind: high or low
height_m: metres above chart datum

Important

These are illustrative datasets with the characteristic timing, range and shape of each station, generated for teaching. They are not official predictions and must not be used for navigation.

For real data, go to the source: SHOM (France), NOAA (USA), the Bureau of Meteorology (Australia), Fisheries and Oceans Canada. Using the real thing is better, and getting it is part of the lesson.

Using them

moonfield tide compare --lat 48.383 --lon -4.495 --timezone UTC \
    --date "2026-08-16T12:00:00Z" \
    --observed 2026-08-16T04:06 \
    --observed 2026-08-16T16:32

Those two times are the high waters listed for 2026-08-16 in brest-2026-08.csv, so you can check them against the file yourself. The --timezone UTC matters: the datetime_utc column is in UTC, and without it your observed times would be read on your own clock and the comparison would be wrong by your offset.