What causes tides? High tide, low tide and tidal range explained
Tides respond to the gravitational forces of the Moon and Sun. Tidal range is the height difference between high and low tide.
Tides respond to the gravitational forces of the Moon and Sun. Tidal range is the height difference between high and low tide.
The mechanism in NOAA’s account
NOAA describes tides as long-period waves that move through the ocean in response to forces from the Moon and Sun. At a coastal location, their passage appears as the recurring rise and fall of sea level.
Three terms to distinguish
High tide corresponds to the crest at a location; low tide corresponds to the trough. Tidal range is the difference in height between those two levels. This definition describes a comparison, not the number of tides in a day.
A worked example
For a made-up tide table using one fixed reference level, suppose high tide is 3.1 metres and low tide is 0.7 metres. The range is 3.1 minus 0.7, or 2.4 metres. These are invented teaching numbers, not a forecast for a real beach or harbour.
Static GK versus a local prediction
This page explains the concept. It does not predict today’s water level at any Indian coast or give boating instructions. A question about the cause of tides needs a mechanism; a question about a local high-tide time needs a dated tide prediction for that specific location.
Publication disclosure
This article was researched and published with AI assistance. No human prepublication review is claimed. Report factual errors through our contact page.
Frequently asked questions
Is this a new event on the publication date?
No. This is a sourced historical profile or static GK explainer, published on 10 October 2026.