Home
Weather Dublin
WeatherRadar
RainfallRadar
TemperatureRadar
WindRadar
LightningRadar
Weather News
Editor's Pick
Discover the app
Weather widget
Contact us
Apps
    Home / Weather News /

    Rolling haar: A sea of fog on the Ligurian coast

15:00
28 August 2023

Rolling haar
A sea of fog on the Ligurian coast

Can't get to the coast this Bank Holiday? Check out this sea fog instead which affected large stretches of the Ligurian coast earlier this year.

Sea fog, known also as haar in the UK and Ireland, forms under certain conditions and is best observed between late winter and late spring.

This is because during spring, the sea reaches its lowest temperatures, while warmer air moving in becomes more common. Sea fog requires the movement of a warm air mass over a cold sea surface.

sea fog infographic

The warm air passing over this colder surface then cools and condenses, like when a person breathes warm air onto cold glass, forming a dense layer of fog or low cloud.

If there is a strong anticyclone (high pressure system) in place, which suppresses convection and forces air to subside, the fog that forms will be more robust.

Weather & Radar editorial team

More on the topic

Meteor shower peaks with mixed visibility. Better view Thursday. . . Wednesday 11 November 2026
Split image showing a UK weather map with temperatures of 0–7°C and snow showers in Scotland, beside a bright meteor streak in a starry night sky.
Wednesday 11 November 2026

Better view Thursday

Meteor shower peaks with mixed visibility
Sunshine returns as gloom lifts. Brighter days ahead. . . Wednesday 11 November 2026
Weather map showing widespread sunshine across the UK and Ireland, scattered wintry showers over northern Scotland and the North Sea, and temperatures of 6 to 9°C.
Wednesday 11 November 2026

Brighter days ahead

Sunshine returns as gloom lifts
Further fog disruption expected. Growing dense overnight. . . Monday 9 November 2026
Weather map showing widespread fog across the English Midlands, with a red fog warning symbol near Nottingham and temperatures of 4–6°C.
Monday 9 November 2026

Growing dense overnight

Further fog disruption expected
All weather news

This might also interest you

Bright and warm conditions take hold. Spring-like outlook. . . Thursday 23 April 2026
Split UK map showing warm temperatures up to 21 degrees in orange on the left and clear sunny conditions with temperatures from 12 to 18 degrees on the right, with sun icons across the country.
Thursday 23 April 2026

Spring-like outlook

Bright and warm conditions take hold
Storm Chandra makes impact. Severe gales & heavy rain. . . Tuesday 27 January 2026
Split image showing strong winds over the UK on a forecast map and widespread rain and snow on a weather radar map.
Tuesday 27 January 2026

Severe gales & heavy rain

Storm Chandra makes impact
Super Typhoon Bavi threatens Taiwan. Up to 1,000 mm of rain. . Weather Videos. Wednesday 8 July 2026
The image shows an intense tropical cyclone over the western Pacific, east of Taiwan and the Philippines. The centre of the system is depicted as a light purple and white vortex with a clearly visible eye, surrounded by a ring of red and orange areas indicating the strongest wind speeds. A white arrow marks the typhoon’s predicted track towards the north-west, in the direction of Taiwan. To the west of the storm lie the Philippines, with the cities of Manila and Cebu; to the north of these lies Taiwan, with Taipei. Further west, the Chinese coast, including Hong Kong, and parts of Vietnam can be seen. The coloured wind map shows predominantly green areas outside the storm’s core, indicating significantly weaker winds. White streamlines illustrate the typhoon’s anti-clockwise circulation in the Northern Hemisphere. The highest wind speeds are concentrated around the eye of the cyclone.
Weather VideosWednesday 8 July 2026

Up to 1,000 mm of rain

Super Typhoon Bavi threatens Taiwan
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy Policy Legal info Accessibility statement

Services

Uploader

Socials

facebooktwitteryouTubelinkList