Analysis of historical heatwaves in the United Kingdom using gridded temperature data

Abstract

AbstractAreas of land in the United Kingdom (UK) affected by heatwaves between 1960 and 2019 have been analysed using a daily gridded temperature dataset. An new metric, the ‘heatwave cumulative area’, defined as the sum of the largest single area on all days within a given heatwave, was found to be useful for distinguishing extreme heatwaves (those which lasted for many days and affected large parts of the UK) from lesser heatwaves. At the time of writing, the heatwaves of July 1975, August 1990 and July 2019 had the largest areas. Positive trends in numbers, durations and areas of heatwaves were found as a result of rising summer temperatures. The maximum areas and maximum temperatures of the heatwaves were found to be highly correlated. The heatwave of 1976, in many ways, remains the most extreme event to have affected the UK, owing to its large area and long duration with temperatures above 30°C.