Extra - August 19, 2014
August down the ages
Last decade wet and dull

By Philip Eden


Long ago when Britain was essentially a rural country and the vast majority of the population worked on the land, August was considered to be the first month of autumn. Dictionaries are unclear about the origin of the word "autumn" but it is interesting that the german equivalent, Herbst, shares a root with our word "harvest". There is no doubt that in medieval England August was an autumn month because it was the first of the harvest months.


The Central England Temperature series, compiled by the late Professor Gordon Manley, allows us to study recent changes in our climate against a background of temperature fluctuations extending back to 1659. After four cold decades in the late 17th century, Augusts were mostly warm between 1700 and 1810 with decadal averages all between 15.4C and 16.3C, but generally cooler months followed between 1810 and 1930. Since then Augusts have been mainly warm except in the 1960s - a decade characterised by marked coolness in most months of the year. The warming trend since then has been consistent until the last ten years; decadal means were 15.3C in the 1960s, 15.7C in the 1970s, 15.9C in the 1980s, 16.9C in the 1990s and 16.7C in the 2000s.


The trend towards drier weather in high summer in the last half century has reversed since 2004. There had been a previous spell of dry Augusts during the early part of the 19th century, but from the 1840s to the 1960s it was a consistently wet month. Recent decadal averages for England and Wales were 100mm in the 1950s, 88mm in the 1960s, 73mm in the 1970s, 76mm in the 1980s, 68mm in the 1990s and 84mm in the 2000s. From 2004 to 2013 the average has climbed further to 89mm.


One would also expect the trend towards drier Augusts to be mirrored by an increase in sunshine hours, and the statistics do not disappoint. Systematic sunshine recording began in England 138 years ago, and these records show four contrasting periods in respect of August sunshine. Sunny months predominated until 1910 with a monthly average of 188 hours, followed by 65 years of relatively cloudy months averaging 170 hours, while between 1975 and 2004 the mean returned to 188 hours. Since 2004, however, the average has slumped to 171 hours.


By Philip Eden


transparent picture
Topics
transparent picture
Archive