Weather & Sea Conditions
Terms from Beaufort Scale to Typhoon, each linked to related terms and to the desks that work with them.
Entries updated May 2026
Related desks
Terms in Weather & Sea Conditions
15 termsBeaufort Scale
A scale of wind force ranging from 0 (calm) to 12 (hurricane force) developed by Rear Admiral Sir Francis Beaufort in 1805.
Cyclone
A general term for a tropical cyclone occurring in the South Pacific or Indian Ocean, characterised by an organised system of clouds and thunderstorms with a defined low-pressure centre and sustained winds of 64 knots or greater.
Doldrums
The equatorial region of calm or light variable winds between the northern and southern trade wind belts, also known as the Intertropical Convergence Zone (ITCZ).
Fetch
The uninterrupted distance of open water over which wind blows in a constant direction, directly affecting the size and energy of waves generated.
Hurricane
A mature tropical cyclone that develops in the North Atlantic or eastern North Pacific Ocean, characterised by sustained wind speeds of 64 knots or greater.
Monsoon
A seasonal prevailing wind in the Indian Ocean and southern Asia that brings heavy rainfall during summer months.
Neap Tide
The tide with the smallest range between high and low water, occurring approximately every two weeks when the sun and moon are at right angles relative to the earth during first and third quarter moon phases.
Sea State
A description of the condition of the sea surface with respect to wave and swell characteristics, categorised using the Douglas Sea Scale from 0 (calm, glassy) to 9 (phenomenal, waves over 14 metres).
Spring Tide
The tide with the greatest range between high and low water, occurring approximately every two weeks when the sun, moon, and earth are aligned during new and full moon phases.
Storm Surge
An abnormal rise in sea level generated by a storm's winds and low atmospheric pressure, over and above the predicted astronomical tide.
Swell
Long-period ocean waves generated by distant weather systems that travel far from their origin, distinct from wind waves generated by local conditions.
Tidal Range
The vertical difference between the highest high tide and the lowest low tide at a particular location.
Trade Winds
Persistent easterly winds that blow from the subtropical high-pressure belts toward the equatorial low-pressure belt, from the northeast in the Northern Hemisphere and the southeast in the Southern Hemisphere.
Tsunami
A series of ocean waves with extremely long wavelengths caused by large-scale disturbances of the ocean floor, typically from undersea earthquakes, volcanic eruptions, or submarine landslides.
Typhoon
A mature tropical cyclone that develops in the western North Pacific Ocean, characterised by sustained wind speeds of 64 knots (119 km/h) or greater.