The hottest heatwave since 1976? This is what the evidence says

By Stephen Burt, Department of Meteorology, University of Reading

There is much febrile comment in the media concerning the current heatwave. A common statement is ‘this is the greatest heatwave since the hot summer of 1976’.

Always a shame to spoil a good story with the truth, but that’s simply not true, and by a long way.

We have temperature records here at the University of Reading extending back to 1908. While these obviously relate to Reading, in ranking and return periods they are reasonably applicable to the whole of southern England.

We had already reached 30°C on three consecutive days this week, and today (Thursday) made it four. the highest temperature of the week was also today, at 32.6°C.

Since 1908, 32 June days have reached or surpassed 30°C – about one year in three, the hottest of all being 34.0°C on 26 June 1976 – much hotter than this week.

True enough, the last time we had three or more consecutive days at or above 30°C in June was back in 1976 (we had 14 consecutive such days 25 June to 8 July) – now THAT’S a heatwave. But we have had many other notable heatwaves more extreme and/or prolonged than this current spell in July and August since 1976.

As recently as 2006 we had four consecutive days with 30°C or more, reaching 35.3°C on 19 July. And back in August 2003, six days in eight reached 30°C, including our all-time hottest day, 36.4°C on 10 August. We are nowhere near these levels!

So, despite what is being reported, don’t be fooled into thinking this heatwave is somehow comparable to summer 1976 (or 1983, or 1989, or 1990, or 1995, or 2003, or 2006…)

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