Ocean City Inlet Tide Prediction Accuracy
Compare TideCheck harmonic predictions against NOAA observed water levels and official NOAA forecasts in real time.
TideCheck computes tide predictions independently using harmonic analysis — the same method used by NOAA and hydrographic offices worldwide. This page lets you verify our accuracy by comparing predictions against real-time NOAA tide gauge observations for 1187 reference stations across the United States. Select a station from the map below, or search by name.
NOAA Reference Stations
Click a station marker to compare TideCheck predictions against NOAA observed water levels. Zoom and pan to explore.
How Verification Works
Harmonic Predictions vs Observed Levels
TideCheck computes tide predictions using harmonic analysis — the same method used by NOAA and hydrographic offices worldwide. Harmonic predictions model the astronomical forces (moon and sun gravity) that drive tides.
Observed water levels from NOAA tide gauges measure the actual water height, which includes astronomical tides plus weather effects: wind setup, atmospheric pressure changes, storm surge, river runoff, and seasonal ocean temperature variations.
Why They Differ
On a calm day, predictions and observations typically agree within 1–2 inches and 1–3 minutes. During storms or unusual weather, observed levels can differ by 1.5–6+ feet from predictions. This gap is not prediction "error" — it represents the real-world weather influence on water levels.
What the Metrics Mean
- RMSE (Root Mean Square Error): Overall prediction accuracy. Under 0.3 ft (0.10 m) is excellent; under 0.5 ft (0.15 m) is very good.
- Mean Height Diff: Average height difference at high and low tide peaks.
- Mean Timing Offset: Average timing difference at high and low tide peaks. Under 5 minutes is typical for harmonic predictions.
Data Sources
Observed water levels and NOAA predictions are from the NOAA Center for Operational Oceanographic Products and Services (CO-OPS). Data is public domain.