Another severe frost overnight with Strathallan pipping Altnaharra to the lowest [18-06] overnight minimum in IONA. Temperatures were at their lowest early across most of Scotland that’s before the southeasterly gradient increased enough to break down the shallow temperature inversion close to the surface. Altnaharra was a classic example of where this happened with temperatures rising from -12.2°C to +0.5°C in just four hours. And guess what where it’s windy wind chill values are low too.
The sub-zero temperatures have lasted over five days at other places in the Highlands such as Loch Glascarnoch and Aboyne though but probably not for much longer.