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
Italy still facing severe weather. Damage in the north. . . Thursday 11 June 2026
Storm damage to buildings and a weather map showing severe thunderstorms near Verona in northern Italy on Wednesday.
Thursday 11 June 2026

Damage in the north

Italy still facing severe weather
Heat is heading for Central Europe. Above 30 degrees. . . Friday 12 June 2026
On the left, a weather map showing the highest temperatures in Europe. On the right, a thermometer against a blue sky
Friday 12 June 2026

Above 30 degrees

Heat is heading for Central Europe
Summer comeback on the horizon. Hot air from Spain. . . Tuesday 9 June 2026
European weather map showing temperatures and weather symbols. A red arrow points from Spain and southern France towards Central Europe, indicating the influx of very warm air. A sun-and-cloud symbol is shown over Germany, indicating pleasant, partly cloudy weather. Maximum temperatures of over 30 degrees are forecast for Spain and Portugal, whilst in Germany, France and the Alpine regions temperatures are mostly between 22 and 25 degrees. The map illustrates a warm south-westerly flow transporting summer air towards Central Europe.
Tuesday 9 June 2026

Hot air from Spain

Summer comeback on the horizon
All weather news
This might also interest you
Historic Storm Éowyn arrives. On this day.... . . Saturday 24 January 2026
Split image showing a person in a yellow jacket struggling against strong winds and heavy rain on a street at night on the left, and an Irish wind forecast map on the right with red and purple shading, gusts up to 75 mph, and a wind warning icon, divided by a curved white line.
Saturday 24 January 2026

On this day...

Historic Storm Éowyn arrives
A frozen start to the weekend. Icy conditions. . . Friday 13 February 2026
UK temperature map dated 14.02 showing widespread subzero values in blue shading, with readings such as −4 in Glasgow, −3 in Dublin, and −2 in London, alongside a blue thermometer icon.
Friday 13 February 2026

Icy conditions

A frozen start to the weekend
Turbulent weather in the Canary Islands. Storm and rain. . . Friday 12 December 2025
Weather graphic showing rain and wind fields over the Canary Islands and a central warning symbol.
Friday 12 December 2025

Storm and rain

Turbulent weather in the Canary Islands
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