It seems unbelievable, but a hot spell of weather has arrived just in time for the start of the school holidays. Stranger still, the hottest place in the UK has not been one of the traditional hotspots of southern England, but somewhere much further north – Aberdeenshire.

The small town of Aboyne was the hottest place in Britain at the start of the week, reaching 26C (79F) on Monday and 22C (72F) on Tuesday. However, Aboyne is better known for much cooler weather, lying in the foothills of the Cairngorms, 140m (460ft) above sea level.

This week’s heat wave began with a large ridge of high pressure that swept up a stream of warm air from the sub-tropics. As the air flowed over the peaks of the Scottish Highlands it swept down the slopes of the mountains and became compressed, drying and warming the air.

This mountain wind is known as a föhn. In the Swiss Alps public notices ban smoking outdoors while a föhn is blowing because of the high risk of fire in the desiccating wind. On May 11, 1861, almost the entire town of Glarus was burnt down during a föhn. The föhn is also infamous for a steep rise in depression, irritability and car accidents. But the föhn in Aboyne this week was a somewhat weaker affair.