The Water tab

The Water tab reads inshore outwards under three band headings. At the beach: the tide height right now with its trend and the next high or low, Against the prediction (how far the measured water is running above or below the tide table), the Tide chart, and Highs & lows for the next few days. Offshore: the NWS Surf zone forecast (rip current risk and surf height for this beach’s sub-zone, two days), and the human-written Offshore forecast with the wave model beside it. Inland: three USGS gauges behind the beach. All tide times and heights are harmonic predictions for Sunset Beach Pier, NOAA CO-OPS station 8659897 — astronomical maths, not a live gauge. Pull down to refresh; the bell in the top right opens tide alerts.

At the beach: the tide right now

The top of the screen is the current predicted height in feet, large, with Rising or Falling beside it and a line such as “High of 4.8 ft at 6:42 PM, in 2 hr”. Heights are above mean lower low water (MLLW), the datum NOAA publishes for this station. If the tide source is down the band shows “No tide predictions available.” or the source’s error.

At the beach: Against the prediction

The one measured number on the screen. Everything else in this band is a prediction, and this section says how far the real water is running from it.

On a quiet day: “The water is running about where the tide table says it should be — no meaningful wind setup on this stretch of coast.”
When it is noteworthy (a quarter of a foot or more): “The water is running a little 0.4 ft above the tide prediction. Expect high tide to reach higher than the table says.” — a little under 0.75 ft, no qualifier to 1.5 ft, well above that. A difference of a foot or more is tinted red. A second row, High allowing for it, adds the anomaly to the next extreme so you do not have to do the arithmetic (table says 4.8 ft at 6:42 PM).
Measured at names the station and how far away and how old the reading is: Springmaid Pier, about 24 nautical miles down the coast.

Sunset Beach Pier lost its instrument in 2008 and has served predictions only ever since, so the anomaly is borrowed from Springmaid Pier (CO-OPS 8661070), the nearest station that measures, on the same straight run of coast. What is borrowed is only the difference between what that station observed and what it was predicted to do — mostly wind pushing water against the coast. The actual water level there, and that pier’s flood thresholds, do not transfer and are never shown. The ⓘ explainer, Water above the tide table, says the same.

At the beach: Tide chart

The predicted curve from six hours ago to eighteen hours ahead, with each high and low marked and labelled with its time and a dashed line at now. The chart’s vertical range is fitted to the curve, so a two-foot swing looks like a two-foot swing. VoiceOver reads it as an audio graph with a summary (“Tide height from six hours ago to eighteen hours ahead, ranging 0.3 to 4.9 feet, with 3 highs and lows in the window.”). If the curve has no points in range the row reads “No curve data in range.”

At the beach: Highs & lows

Up to the next eight highs and lows, from an hour ago forward — each row is High or Low, the day, the time and the height. The predictions behind them run about two weeks ahead, which is also how far ahead tide alerts can be queued.

Offshore: Surf zone forecast

The NWS Wilmington Surf Zone Forecast for zone NCZ110, Coastal Brunswick, which names Sunset Beach and splits rip current risk and surf height into two sub-zones: East of Ocean Isle Beach and Ocean Isle Beach West. Sunset Beach lies west of Ocean Isle, so the west row is this beach specifically, and that is what the app shows. The two frequently disagree — on the day the app was built, east read Low and 1–3 feet while west read Moderate and 2–4 feet.

The section shows:

Any headline the forecaster issued, as a warning row — for example “MODERATE RISK OF RIP CURRENTS IN EFFECT FROM 6 AM EDT SATURDAY THROUGH SATURDAY EVENING”.
The forecast’s labelled days — normally today and tomorrow — each with the day name, the rip current risk (Low, Moderate, High, colour-coded), Surf 2 to 4 feet, and the weather line.

Days beyond the labelled table are written as one paragraph for the whole zone, and the app deliberately does not show them here; they appear on the This week planner marked whole zone, not this beach. If the product cannot be read the section says “The forecast text couldn’t be read.” The same forecast feeds the Surf and Rip risk readings on Today.

Offshore: the Offshore forecast

Titled with the current forecast period — Offshore — Tonight, Offshore — Saturday — with the zone id AMZ252 at the right. It is the NWS Coastal Waters Forecast for the water from Cape Fear NC to Little River Inlet SC, out 20 nautical miles, written by a forecaster at the Wilmington office. Only the current period is shown; the product itself runs to about a week.

Row	What it shows
Wind	The period’s wind, in the forecaster’s words
Seas	Sea height, with the swell breakdown as the caption when the forecaster gave one
Wave model	Open-Meteo’s modelled total wave height in feet, with period and direction — the second opinion
Weather	The period’s weather, in prose
Next few days	The forecast synopsis

Two sources sit side by side on purpose. The forecaster is describing twenty nautical miles of open water; the wave model is a ~25 km grid whose nearest point is several miles offshore, and the footer says so: “The wave model’s nearest grid point is about 6 miles offshore, which is most of why it and the forecaster disagree.” Where they disagree, both are shown rather than one being quietly preferred. Seas offshore run larger than the surf at the shoreline, so none of this is a forecast for the swash — and nothing here measures waves at this beach, which remains a genuine gap.

Inland: Inland water

Three USGS gauges, none of them in the sea. They are here because what the rivers carry reaches this coast a few days later, and runoff is most of why the nearshore water goes from clear to murky. The section and its Inland heading only appear when at least one gauge reported.

Row	Gauge	What it tells you
Waterway temp	Intracoastal Waterway at Nixons Crossroads, about 12 miles away	The waterway’s temperature — not the sea. Today’s Water reading is the buoy in the sea at the beach; in spring the two differ by several degrees
Oxygen	Same gauge	Dissolved oxygen, mg/L
Conductance	Same gauge	Specific conductance in µS/cm — tracks saltiness, so a drop after heavy rain is freshwater runoff diluting the waterway
Turbidity	Waccamaw River above Conway, about 30 miles away	Sediment, in FNU — the number behind the runoff sentence
Warning row	Nixons Crossroads	”The waterway is running backwards on the tide right now.” when discharge is negative — the tide pushing the waterway upstream, not a fault
Prose	Waccamaw	”Regional rivers are running clear — little recent runoff.”, “Some sediment in the regional rivers after recent rain.”, or “Rivers are running muddy (N FNU) — expect murkier nearshore water and poorer visibility.”
Prose	Cape Fear River at Lock 1, about 90 river miles inland	”Cape Fear discharge is low (… cfs). Little plume pressure on the coast.”, moderate, or “Cape Fear is running high (… cfs) — more freshwater and sediment heading for the coast over the next few days.”

The footer names which gauge each reading came from and ends “None of these is a reading from the surf.” A Swim advisories & bacteria button switches to Today, because the state’s bacterial testing is a different programme on a different screen — see the Today tab.

Where each number comes from

Section	Upstream
Tide now, Tide chart, Highs & lows	NOAA CO-OPS predictions, station 8659897 Sunset Beach Pier
Against the prediction	NOAA CO-OPS station 8661070 Springmaid Pier — observed minus predicted
Surf zone forecast	NWS Wilmington Surf Zone Forecast, zone NCZ110, sub-zone Ocean Isle Beach West
Offshore	NWS Wilmington Coastal Waters Forecast, zone AMZ252; Open-Meteo Marine wave model
Inland water	USGS gauges 02110777, 02110550 and 02105769

Cadence and limits for each are on Where every number comes from.

Next steps

Alerts and notifications Tide reminders are scheduled on the phone from these predictions; here is how they work.

The Today tab Surf, rip risk and swell at a glance, and the water quality card.

Where every number comes from Every upstream source with cadence and known limits, including why there is no wave sensor here.

Limits and what it doesn't know One beach, no lifeguards, no wave or water-level sensor, and the other stated gaps.