On Monday 2nd July we released our provisional climate statistics for June: an exceptional month resulting in a number of new climate records, including the warmest June on record for Wales and Northern Ireland.
A provisional national high temperature record for Scotland was also set with an observation of 33.2 °C recorded at Motherwell, Strathclyde Park on the afternoon of 28th June. Temperatures in the low 30s were observed at a number of sites in the central belt of Scotland, with 31.9 °C at Glasgow, Bishopton, and 33.0 °C was also recorded in Wales at Porthmadog, Gwynedd. Making it undoubtedly the hottest day of the year so far for the UK. However subsequent information has cast some doubt on the Motherwell measurement for that day, meaning that we will not be able to accept it as an official new record for Scotland, which will remain as 32.9 °C at Greycrook, Scottish Borders from 9th August 2003.
How do we verify records
Dr Mark McCarthy is the head of the Met Office’s National Climate Information Centre. He said: “At the Met Office we manage a network of weather observing sites across the UK. This network is comprised of approximately 259 automatic weather stations managed by Met Office and a further 160 manual climate stations maintained in collaboration with partner organisations and volunteer observers. We have previously written about how our temperature records are measured and verified.
“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.”
Why has it been rejected?
Unfortunately in this particular instance we have evidence that a stationary vehicle with its engine running was parked too close to the observing enclosure and the Stevenson screen housing the thermometers during the afternoon of 28th June. Although the measurement appears plausible given the weather conditions that day we cannot rule-out the potential for contamination of the measurement by this non-weather-related factor.
The Met Office works closely with collaborating organisations who host or manage weather stations on our behalf. The observing site at Motherwell makes a very valuable contribution to our observing network, and the rejection of this particular record does not detract from that or from the hard work of those making the observations. We will continue to work closely with our partners at the site, and across our network, to maintain a high-quality climate-observing network for the nation.
What does this mean for the June heatwave?
The spell of weather at the end of June and into July is without doubt a notable heatwave for the UK, and particularly for Scotland and Wales, with some very high temperatures on 28th June. The rejection of the Motherwell observation for that day does not detract from that. More detail about June and other statistics can be found on our climate pages