Aboyne in Aberdeenshire was the frostiest place in IONA recording 25 air frosts in the 30 nights of April 2021. Probably a local record, in what was the frostiest April in a hundred years according to the UKMO. Loch Glascarnoch missed at least two nights of frost due to a comms issue with their AWS which might have boosted their joint fourth ranking. The spread of air frosts further east and away from the immediate coast was pretty uniform, with Benson and Topcliffe both registering 18 air frosts during the month. The cold spell with the sub 510 dm thicknesses at the start of the month meant that even the small island of Baltasound in the Shetlands had 9 frosts.