How Hot was it Really this Summer Across the UK? (Photo Credit: UK Met Office and Climate.gov)

With winter having made it’s presence across most of the United States last week, it is hard to remember the heat of summer. However, what many across the USA do not realize is that this past summer, 2018, was one of the hottest on record for the United Kingdom (UK), which encompasses England, Wales, Scotland, and Northern Ireland. More accurately, the summer of 2018 is tied for the hottest summer on record in the UK with the summers of 1976, 2003, and 2006 according to the UK Met Office.  To give more perspective on this, records have been kept since 1910.

The UK Met Office reports that the average summer temperature for 1976, 2003, 2006, and 2018 were within 0.03˚C of one another.  The average summer temperature for 2018 was 15.80˚C, while the average recorded temperature for the other three years were as follows: 1976 - 15.77˚C, 2003 - 15.77˚C, and 2006 - 15.78˚C. This is too small of a difference to declare that one of the four summers was actually warmer than any of the others due to error. Therefore, all four summers officially share the record for the hottest summer at 15.8˚C. Even though the UK summer as a whole only tied for the hottest on record, England itself saw the hottest summer on record at 17.2˚C. This beat the previous record set in 1976 at 17.0˚C.
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One reason this past summer was so hot in the UK was due to the heatwaves seen across Europe beginning in late June. The definition of a heatwaves varies across the globe but in general a heatwave is defined as ``a period of abnormally and uncomfortably hot and unusually humid weather. Typically, a heat wave lasts two or more days” (NOAA NWS Glossary 2018). The UK, broadly speaking, uses 30˚C or higher for two or more days as their criteria for a heatwave. The initial heatwave began, roughly, on June 23, 2018. After this, additional heatwaves occurred on and off until August, when temperatures dropped back closer to average. When all was said and done there were nine consecutive days in which the temperature topped 30˚C somewhere in the UK. During this time, the jet stream was consistently located further north than normal, allowing a nearly stationary high pressure system to set up over Europe. This drove hot, dry air northward into the region. Shockingly, although the heatwave that hit this passed summer was intense, the summer of 1976 saw 18 consecutive days with temperatures above 30˚C somewhere in the UK. However, despite the longer duration of consecutive days above 30˚C, 1976 was not as dry as 2018. In fact, the first half of summer in 2018 was the driest in 50 years across the UK. For a more in-depth comparison of the two summers see https://www.bbc.com/news/uk-44943672. 

To learn more about other high-impact weather events occurring across Europe, be sure to click here!

© 2018 Meteorologist Sarah Trojniak, Ph.D.