Altnaharra is reporting a (rounded) -14, and even IMBY we've lost a degree in the last hour, currently -3.5 with a low so far of -3.6.

https://www.trevorharley.com/coldest-days-of-each-year-from-1875.html 

Trevor Harley's handy site reports a low last year of -14 (at Dalwhinnie), so perhaps we've beaten it.

EDIT: Turns out Altnaharra is reporting -13.6. Close, but not quite there...

Coldest I can remember without snow cover in Cambridge was -9C in I think around 1990.

It's -6C here now, everything lovely and white. If cloud or fog stays away could be a tad colder tonight? It's actually been good this winter for frosts so far. 

As always it's so finely balanced on these radiation nights, and all the elements have to be in place. The gradient winds have finally dropped towards the end of the night but too late to get a full night's cooling. In places where the cold pools of air persist it will stay very cold today and temperatures will fall like a stone this afternoon - I wouldn't be surprised to see something like -15C before 6pm.

Deep snow cover, clear skies, max of 1C the previous day and that is as low as it can get at the heart of winter.

There are no words to do justice as to how utterly useless, lame and embarassing this 'cold' spell. Pitiful doesn't even begin to describe it.Just one night has got lower than -0.4C this week. 

9-12cm of snow and 17 hour nights with maxes of 1-2C and we can only manage one night colder than what was achieved on 20th May 2012 with only 7 hours of darkness, a double digit max and, needless to say, no snow cover.

Awful.

Insulation due to some cloud cover and a breeze mixing the air at a coastal location will give these expected temperatures. If we lose both tonight it will end up much colder.

Now down to -6.8 at 9am hourly reading at Gogarbank

The snow cover isn't thick, but it's remained unchanged - and still looks absolutely pristine

-14.4C the lowest at Altnaharra up to 9am.

Altnaharra hit -14.4C before 9am so colder than any day last year.

Looking at that list I hadn't realised there was a -23C as recently as 2021.

I seem to remember you and I discussing that occasion quite a bit as it happened!

Local effects were in full play that night; I recorded -15C in the main Dee valley but 1 mile north of me in a side valley it was down to -23C.

Well my memory clearly isn't what it was!

As a result of that reading, last night's official minimum temperature at Gogarbank has been corrected to -6.8°C as each official observation day ends at 09:00 UTC every morning which at this time of year is 9am GMT.

That is exactly the same minimum temperature as what was recorded on 2 December 2023 and to find the last time that it was colder than that, you have to go back to 8 March 2023 when the temperature there got down to -7.5°C.

However, that happened in the spring of 2023 and not in the actual winter so to find the last time (other than 2 December 2023) that the overnight minimum temperature was below what we had last night in the actual winter, you have to go back to 16 December 2022 when the temperature there got down to -7.7°C.

I'm pleased you finally have your winter wonderland, we down here will need to wait for a continental easterly, with the extra warming, that is now the only way we can get snow to stick these days

We still have a covering of snow* on lawns and other areas where it settled most readily on Wednesday so if anything the low last night was a bit disappointing. 

*by snow I mean refrozen partially melted slushy stuff!

Still -13.0 at noon at Altnaharra.

If the conditions stay calm and clear then it could get pretty cold tonight up there.

Met Office forecast says it should be -3C by 1pm, I doubt it... 

https://weather.metoffice.gov.uk/forecast/gfkgdgj2j#?nearestTo=Altnaharra%20 (Highland)&date=2025-01-10

FWIW the lowest daily max on record is -15.9C, so that's not in danger! I wonder if it could stay below -10 until 9am tomorrow though?

I thought the lowest all time maximum is -19C at Braemar in 1982.   🙂 

According to weatherobs.com, there are actually a few locations in the north of Scotland which were still experiencing minus double figures temperatures at noon.

Here in Edinburgh, you have to go all the way back to 11 February 2021 to find the last occasion on which we experienced minus double figures temperatures here in Edinburgh.

On that day, the temperature at Edinburgh Gogarbank got down to -12.6°C but the remarkable thing about this is that we still weren't able to record any ice days with that at the time, even though I can vaguely remember Brian recording one in his own neck of the woods in the south of England (I could be wrong with that though).

With this latest cold spell, we have never even close to getting minus double figures here in Edinburgh although we did get down to -8°C at the airport last night.