Tideglass

Tideglass is a free, offline tide instrument for iPhone and Apple Watch. Designed like a vintage marine chronometer in brass and navy — no ads, no accounts, no internet required.

FEATURES
◆ ~8,000 tide stations worldwide, all bundled in the app
◆ Pannable 24-hour chart with a static centre cursor — swipe to scrub ±7 days, with a magnetic snap when you cross "now"
◆ 30-day histogram: every day's maximum high and minimum low as paired bars, with the spring/neap pulse plain to see
◆ 12-month envelope: a smoothed year-at-a-glance view of the highs and lows around your spot
◆ Top-5 tide rankings: see the biggest highs and deepest lows in any visible window
◆ Sunrise, sunset, moon phase, and your nearest station's name at a glance
◆ Mechanical-drum readout for time and water level, with selection haptics as you scrub
◆ Apple Watch standalone — runs without iPhone, same instrument feel on the wrist

PRIVACY
◆ Location is read only on device to find your nearest tide station — nothing is transmitted, stored, or shared
◆ No accounts, no analytics, no ads, no tracking

DATA
Tide harmonics derived from the open OpenWaters database (NOAA + TICON-4). Predictions are sub-hour accurate at most reference stations. Subordinate stations rely on time and height offsets from a parent station.

RECREATIONAL USE ONLY. Not for marine navigation. Always consult official hydrographic publications for safety-critical decisions.