Weathering a storm of extremes

Spring 2014 is expected to be the third warmest on record, beaten only by 2007 and 2011. After what has seemed like more than our fair share of extreme weather in the recent past – floods, storms, cold snaps etc. – the more temperate conditions this spring hardly seem to be record breaking or extreme. Is it worth paying any attention to stories about record breaking weather or is it just too easy to select records to make a story?

The cliché is that the British always talk about the weather despite the fact that it is largely unremarkable compared to much of the rest of the planet. Some of the recent temperature and rainfall records that have been broken include:

  • Warmest April (2011)
  • Warmest spring (2011)
  • Warmest October day (2011)
  • Wettest January (2014)
  • Wettest April (2012)
  • Wettest June (2012)
  • Wettest winter (2013/14)

Winter 2013/14 was also said to have had more ‘very severe gale days’ than any other winter in a series back to 1871. While this list seems quite long already, particularly the wet records, it can be added to with near misses (2011 was the second warmest year ever, 2012 the third wettest) or with series for the home nations (December 2013 was the wettest month ever in Scotland, 2012 the wettest ever year in England).

We can rapidly expand the number of records broken by looking at more detailed data. This could be daily series (online back to 1878 for temperature and 1931 for rainfall), regional data, individual stations data, or max and min not just means. Combining the daily figures lets us look at a potentially vast range of rolling time periods such as the longest with absolutely no rain recorded,13 days in early summer 1939; or the longest with more than 1 mm of rain per day, 31 days in late 2009 (some way short of the Biblical 40 days and 40 nights).

We can look at records for individual dates. 12 new highs were set in 2011, but none in 2013. The warmest and coldest Christmas days since 1878 were 12.9oC in 1900 and ‑11.2oC in 1878. Mid summer mean temperatures have varied from 4.0oC in 1903 to 29.5oC in 1941. The latter came at the end of a hot spell that prompted George Orwell to write:

We have all been in a semi-melting condition for some days past. It struck me that one minor benefit of this war is that it has broken the newspapers of their idiotic habit of making headline news out of yesterday’s weather.

There are also different series that cover ‘national’ data. The UK rainfall and temperature series go back to 1910, while the England and Wales rainfall and Central England Temperature series go back to 1766 and 1659 respectively. The shorter the series the easier it is to break a record.

If you look at the data in its finest detail and across different series you get a vast number of possible records that could be broken and it should be no surprise when the more obscure ones are.

How does knowing this help us when we hear a new record has been set? Ideally we would ask ourselves how many records were not broken today, this month, last season etc? This context would help us judge the importance of the new record and what it might say about our weather and possible changes in our climate. Such instant calculations are beyond most people, but being aware that the numbers involved can become very large is useful context in itself. After that an interested reader can look to the most reputable authorities on the subject – the Met Office in this instance – to see which records they report on, and where possible look beyond news releases which generally go through the filter of a media office.

The kind of ‘data mining’ exercise that simply looks for any record or unusual value – to sell a story, product etc. – can apply to statistics on any subject and is more prevalent with the growth of big data. Weather data are a useful illustration only.

We don’t yet know whether recent weather events will go down in history the way that the storms of 1953, the Big Freeze of 1963 or the summer of 1976 have. Some of the weather we have had in past few years can rightly be called extreme, for the UK, but plenty has not. We can be sure that even when there is little going on with the weather, it always gives us plenty to talk about and avoids those clichéd no-go areas of religion and politics.

Paul Bolton