July 1, 2015, by Lucy


Summer is here, and temperatures in many parts of the UK are predicted to reach over 30 degrees C later today on what is expected to be the hottest day of the year so far, prompting much talk of heatwaves past and present in conversation and on social media (#UKheatwave). The hot weather has also prompted us to search our growing database for accounts of heatwaves, some of which we’ll share with you in this post.

What is a heatwave?

The Met Office describes a heatwave as “an extended period of hot weather relative to the expected conditions of the area at that time of year”. The official World Meteorological Organization definition of a heatwave is “when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C, the normal period being 1961-1990”. The present high temperatures are not expected to last long on this occasion, with thunderstorms and cooler temperatures tomorrow.

An average temperature of 30 degrees C by day, and 15 degrees C by night is likely to trigger health warnings from the Met Office and Public Health England. The UK experiences only occasional heatwaves, you might remember the 10 day heatwave of August 2003 when a record maximum temperature of 38.5 °C was recorded at Faversham in Kent. That period of hot weather is thought to have led to around 2,000 heat-related deaths in the UK.

Hyde Park in the heatwave of August 2003, Stephen Craven, geograph.org.

Hyde Park in the heatwave of August 2003, Stephen Craven, geograph.org.

Historical heatwaves

The majority of our historical records of extreme weather are descriptive accounts rather than instrumental observations so we cannot be sure that the described conditions match the contemporary definition of a heatwave. It is also quite unusual for a period of extremely hot weather to be described as a ‘heatwave’. What we can be sure of is that the events below were very hot!


The oldest period of extreme heat we have picked up in our searches so far is that of the summer of 1607, detailed in some pages of historical notes relating to Arlingham (12 miles south of Gloucester)  in the Cokayne (Rushton) collection:

The somer following there was a most extreme hot somer insomuch that many dyed with heate & within the compass of a yeare in 1607 there was a wonderful frost, after all which followed a dearth, C739, Northamptonshire Record Office.

1778 & 1779

There are a few instances where hot summers follow hot summers. In time we’ll be exploring these ‘combination’ extreme events in more detail to explore whether impacts are multiplied, or lessened as a result of better preparation.

John Clifton of Barnwell, Northamptonshire, records the heat of summer 1778:

  • Monday 22nd June – a very hot day
  • Tuesday 23rd June – a very hot day
  • Wednesday 24th June – a very hot day
  • Thursday 25th June – a very hot dry day
  • Friday 26th June – a very hot dry day
  • Saturday 11th July  – a dry day & very hot
  • Monday 13th July – the most sultry hot day we have had this summer
  • Tuesday 14th July – an excessive hot day again
  • Wednesday 15th July – a sultry hot day
  • Thursday 16th July – a sultry hot day
  • Friday 17th July – a hot dry day again
  • Saturday 18th July – a very hot dry day. My self about home & watering my garden… The driest & most hot summer that we had these 20 years, but thank god there are very fine crops of grain all over the nation, ZA8742, Northamptonshire Archives.

His day book entries for the following year are remarkably similar:

  • Friday 9th July – a searing hot day
  • Saturday 10th July – a searing hot day
  • Wednesday 14th July – a searing hot day
  • Thursday 15th July – a searing hot day again
  • Friday 16th July – a very hot day, ZA8743, Northamptonshire Archives.

1808 & 1809 – fatal heat

A similar pair of hot summers occurred in 1808 and 1809, with oppressively hot spells in July of 1808 and May of 1809, the former being enough to cause serious health problems and death:

At Winkburn, Nottinghamshire, Peter Pegge-Burnell records in his diary:

  • July 10-11 – hot days
  • July 12 – an extremely hot day, thermometer in shade against a brick wall 92
  • July 13 – still hotter
  • July 17 – very hot again, have got 42 loads of capital hay, DD/CW/8/5/26, Nottinghamshire Archives

At Exeter, as recorded in Samuel Poole’s diary:

12, 13 & 14 July 1808 was the hotest [sic] weather known in this city for 30 years particular the 14th the weather glass at hoscock [place name?] in the afternoon was up so high as eighty one and a very severe storm of thunder and lightening on the evening of the 14th was ever known in this city but no damage was done, 5183M/Z/1, Devon Record Office.

Confirmed in the Parish Register for Uffculme, Devon:

1808 – A most remarkable hail & thunder storm. The weather for many days previous to the 15th July 1808 had been remarkably hot, 1920A/PR/1/6, Devon Record Office.

And in the Parish Register for Clipston, Northamptonshire, a description which gives a good indication of the severity of the heat, and through the inclusion of an instrumental measurement of temperature, suggests that conditions were more extreme in Central England than in the South-West:

1808. July 13, 14 – These two days were very hot the thermometer 90 in the shade, many persons at work dropped down dead in many of the neighbouring parishes and many sent home who recovered. We have reason to be thankful for a prospect of an early & plentiful harvest. Last winter the coldest & longest ever known, CLIPSTON 70P/3, Northamptonshire Archives.


The only other extreme heat event for which we have a record of associated deaths in the database is 1826, when the Wakefield family of Shelford’s commonplace book records:

In the year 1826 a very dry summer it did not set in till the later end of may  – in the 18 19 July a very hot Wednesday a many people that droped [sic] and died with the hot sun, DD2236/1, Nottinghamshire Archives.

A couple of letters in Manuscripts and Special Collections from John T. Townshend, 2nd Viscount Sydney, to the Hon. John R. Townshend also detail this heat:

Grosvenor, 28th June 1826. We heard the day before yesterday of the safe landing… A very hot summer it is. Sunshine is so delightful to me that I do not grumble at the heat…

29th June 1826… All sunshine here & boiling hot, so long a drought has not long been remembered. From Ireland they have no hay, no potatoes, cattle die from want of water. I am much too great a philosopher to grumble in England too at sun shine. It is cheering to see it & I enjoy it… Sy, THF/X/3/6/6/1-3, Nottingham University Library, Department of Manuscripts and Special Collections.


Famous heatwaves of the twentieth century happened in 1906 and 1911. Looking in more detail at the 1911 event gives us an opportunity to highlight one of the more unusual sources in county archives that have made it onto our database, the ‘batch books’ of Frears and Blacks bakery in Leicester:

  • Week beginning 3 July – weather very hot all the week, glorious summer
  • Week beginning 24 July – weather still holds very hot & dry, not any rain for over 3 weeks
  • Week beginning 7 Aug – weather excessively hot, wed was hottest day for 70 years, thunderstorm on Thur & Fri, hot again Saturday
  • Week beginning 14 Aug – weather very hot all the week, we want rain very badly
  • Week beginning 21 Aug – weather, drought ended at last, heavy thunderstorm last Sunday, showery all week, DE1576, Leicestershire, Leicester and Rutland Archives.

Imagine baking all day in this heat! The high temperatures of 1911 were accompanied by a lack of rain, leading to a severe drought across much of the UK with serious impacts, particularly on agriculture.


As usual we’d love to hear from anyone with memories of UK heatwaves or photos of the current hot conditions. Stay cool…


Posted in Archive visitsProject themesWeather extremes