As heat and humidity moved in from Iberia, the mercury soared to 29.4C in Kinloss, Moray, with Aviemore in the Highlands not far behind at 29C, the same as Bangalore and Rhodes.
Although the temperatures were the highest so far in Scotland for 2015, they did not compare to the heatwave conditions in the south-east of England.
Forecasters recorded a temperature of 36.7C at Heathrow Airport early yesterday afternoon, making it the hottest day in July since records began.
Urgent health warnings were issued and paramedics dealt with a surge in calls due to the extreme conditions.
Network Rail instructed train companies to slow down at vulnerable locations due to the risk of tracks buckling, while the AA said its patrols had reported roads melting in places. Despite the hot conditions, yesterday evening brought thunderstorms and heavy showers to parts of Scotland, with forecasts of more to come after the heat and humidity injected a significant amount of potential energy into the atmosphere.
Stormy conditions moved in over the Western Isles by 5pm and the Met Office put in place yellow “be aware” warnings until 11:50pm last night for further thunderstorms breaking out across Lothian & Borders, Fife, Tayside, and the Strathclyde area
With a hot and humid airmass over much of the UK, the Met said the storms could be “severe” with up to 20 to 30 millimetres of rainfall in an hour in places.
The forecasts were a marked difference to the warm conditions earlier in the day. Although nowhere came close to breaking the existing Scottish record temperature of 32.9C – set on 9 August 2003 in Greycrook in the Borders – the mercury reached the high twenties in most places.
In the Highlands, one of the hottest areas, temperatures of 28.1C were recorded in Drumnadrochit and 28C in Altnaharra. It was cooler in Edinburgh with temperatures at 1pm of 22.2C, while in Glasgow the mercury nudged a little higher to 25C, with cloud cover obscuring much of the sunshine.
Thousands of people flocked to parks and beaches while in Aberdeenshire, hundreds of people descended on Stonehaven’s outdoor pool.
Down south, however, the London Ambulance Service said it had seen call-outs to people fainting increase by more than a third (35 per cent) compared to the same day last week, and a 28 per cent hike in the number of calls it has received over the same period.
Network Rail instructed train companies to travel at reduced speeds due to the heat, with routes affected including Abellio Greater Anglia trains between London Liverpool Street and Ipswich and First Great Western services between London Paddington to Bourne End and Henley-on-Thames. Virgin’s East Coast line between Leeds and London Kings Cross also ran a reduced service.
A spokeswoman for Network Rail said metal rail tracks could get 20C hotter than the air temperature, meaning they could reach 56.7C, prompting fears the steel could expand and buckle.
The AA meanwhile said its patrols in parts of England said the Tarmac had been melting in places, with one motorcyclist putting the stand down on his vehicle, only for it to sink into the road surface.
A spokesman said: “The AA are receiving anecdotal reports from patrols that show that in places the road surface is softening, but there are no widespread problems at the moment. But if this continues we could start to see that. We have been very, very busy today.”
Laura Young, forecaster with the Met Office, said that today was shaping up to be another fine summer’s day for Scotland, although not as warm.
She said: “Temperatures are still likely to be in the low to mid twenties in most areas but it will be a bit fresher. There will be much more in the way of cloud but generally a dry start with one or two isolated showers, but they are not going to be particularly thundery. It’s a good start to the Scottish school summer holidays.”