Scotland's hottest day record 'not accepted' by Met Office

People sunning themselves in Glasgow's George Square last Thursday

Scotland's highest ever temperature reading has been rejected by the Met Office over fears it could have been affected by a parked vehicle.

On Thursday 28 June, a temperature of 33.2C degrees was measured at Strathclyde Park in Motherwell.

The Met Office now says a stationary vehicle with its engine running was parked too close to the equipment.

It said that although the measurement was "plausible" it could not rule out the potential for contamination.

It means that last Thursday was not officially the hottest day ever in Scotland.

A temperature of 32.9C recorded in August 2003, at Greycrook in the Borders, remains the highest ever.

The "weatherproof" membrane of Glasgow Science Centre melted in the sun

Provisional figures from the Met Office said average temperatures had made it the fourth hottest June ever experienced in Scotland.

It was the fourth sunniest June for the UK overall.

The temperatures were so hot on Thursday 28 June that the "weatherproof" membrane on Glasgow Science Centre's roof melted and dripped black "goo" down the building.

A blog from the Met Office said temperatures in the low 30s were observed at a number of sites in the central belt of Scotland on that day, with 31.9 °C recorded at Bishopton in Renfrewshire.

Many took the chance to enjoy the sun at Gourock lido

Dr Mark McCarthy, head of the Met Office's National Climate Information Centre, said: "At first review the Motherwell record appeared plausible given the wider conditions on the day and was therefore reported as such.

"However, for all new records we undertake further careful investigation to ensure that the measurement is robust.

"This investigation includes statistical analysis of the station data, evaluation against neighbouring sites, and in some cases an additional site visit to check for unexpected issues with the instrument enclosure or equipment to ensure the measurement meets our required standards."

The thermometers are housed inside a box with a Stevenson screen

White box

Jim Dale, a senior meteorologist at British Weather Services, told BBC Scotland he was surprised that a vehicle had been allowed so close to the Stevenson screen, behind which the thermometers are kept.

He said: "Temperature is measured in a white box, essentially, with slats.

"That is to keep it in the shade because all temperatures are measured in the shade not in the full sun.

"The reason for the slats is to allow a passage of air going around it, almost like a breeze.

"If a car engine exhaust is nearby it is going to be warm and therefore you are going to be in a situation where it could put the temperature up slightly."

Mr Dale said if you were dealing with record temperatures there could be no hint of it being inaccurate.