Freezing fog: Met Office issues travel warning as temperatures plunge as low as -9C across Scotland

Glasgow has been gripped by freezing fog for the second successive day, as the Met Office issued a warning for anyone heading out on the roads as temperatures hovered below freezing across Scotland.

The warning comes after the mercury dropped to -9.1°C in the village of Braemar in Scotland on Tuesday. Conditions across Scotland and Northern Ireland have continued to be particularly cold and frosty, with some dense patches of fog.

Dog walkers in Cathkin Braes, as freezing fog persists for a second day in Glasgow and the surrounding area. Picture: John Devlin | John Devlin

Met Office meteorologist Alex Deakin said: “If you’re stuck in fog all day, temperatures are not going to get above freezing.”

Overnight the fog is due to thicken again, particularly across south-west Scotland and parts of Northern Ireland.

Fog on the river Clyde at the South Portland Street Suspension Bridge. Picture: John Devlin | John Devlin

For the vast majority of the UK, it will be a dry night. However, during the early hours of Thursday, thickening cloud over eastern areas is likely to bring some rain and drizzle, Mr Deakin said. He said temperatures where the cloud holds up will be above freezing.

“Where it’s clear, [temperatures will be] well below freezing across Scotland, -3C, -4C,” he said. “That’s towns and cities, some sheltered glens much, much lower than that.”

The outlook for the weekend is that some fine weather and sunshine will emerge as high pressure dominates. But there will also be overnight frost and fog.

Fog covers Cathkin Braes Golf Course. Picture: John Devlin | John Devlin

Patchy rain will begin to arrive across the north during the weekend, the Met Office said. A yellow weather warning was issued for fog across parts of Scotland on Tuesday, extending to 11am on Wednesday.

Glasgow, as well as North and South Lanarkshire, Renfrewshire and Dunbartonshire, were all covered by the alert.

The thick fog was expected to make travel conditions difficult, with those using the roads urged to check conditions before making their journeys.

A Met Office spokesperson had said: "Areas of freezing fog will continue to make travel conditions rather difficult overnight and Wednesday morning."

On Monday, the NHS in the north west advised people to take extra care to avoid a fall in the wake of a yellow cold weather alert.

Last year, more than 86,000 people contacted North West Ambulance Service because of a fall and 40 per cent of emergency call-outs to people who had fallen were during the colder winter months, it said.

What is freezing fog?

According to the Met Office, freezing fog forms in the same way as normal fog and is caused by the land cooling overnight under clear skies.

An explanation on the forecaster’s website reads: “If there are clear skies, the heat radiates back into space, leading to cooling at the earth's surface. This results in a reduction of the air's ability to hold moisture, which allows water vapour to condense into tiny water droplets, eventually leading to the formation of fog.

“When fog forms in temperatures that are below freezing, the tiny water droplets in the air remain as liquid. They become supercooled water droplets remaining liquid even though they are below freezing temperature.”