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UK Precipitation Stats – 2013

January 16, 2014

By Paul Homewood

 

I keep meaning to get around to this, and then something else crops up! So, here goes – the round up of stats for last year’s precipitation in the UK.

 

2013_17_Rainfall_Anomaly_1981-2010

 

Overall, the year was a pretty dry one, with very few places above the 1981-2010 average. With 1086mm of rain, last year ranked 53rd wettest , out of 104 years

 

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The trend remains slightly above the 1981-2010 baseline.

 

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In the longer term England & Wales series, the year was also thoroughly unremarkable, ranking 117th wettest, out of 248 years.

 

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Seasonal Trends

 

Seasonally, we see that winter precipitation continues to trend down, although last year was slightly wetter than average. (This, of course, only runs up to 2012/13 winter).

Summer was markedly dry, the 14th driest since 1910, but the trend in the last couple of decades is still noticeably up. This is significant because Met Office projections have been consistently pointing to the opposite, drier summers.

Spring and Autumn show nothing out of the ordinary, and the trends look pretty stable as well.

 

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Raindays

As the issue of whether heavy rainfall events are becoming more common seems to be a subject of debate currently, let’s have a look at the rainday data.

 

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As we saw with winter rainfall, the average daily rainfall, on the days when it does rain, has increased since the 1960’s, the first time the Met Office started to keep rainday data.

However, the upward trend seems to have peaked in 2008, and the 5-Year average is back where it was in the early 1990’s, despite the very wet year of 2012.

As I also noted with the winter stats, comparison with the 1960’s and 70’s can be highly misleading, as they were unusually dry decades. There appears to be a very clear correlation between total annual rainfall, and the average rain per rainday. Years with high rainfall tend to have much higher averages. The graph below shows this well.

 

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The inference then is that any analysis, using 1961 as a start point, is overestimating the long term increase in average rainfall. If long term precipitation trends remain stable, which they seem to be currently in all seasons except summer, there appears to be little evidence that heavy rainfall events will become either more common or intense.

2 Comments
  1. Lance permalink
    January 17, 2014 1:47 am

    Interesting…
    Here in southern Alberta, we have had a long good stretch of ‘good’ timing of wet weather for the summer grain crops….from my stats…above normal…just wait though, we are a ‘semi’ arid province here….so when it goes back to ‘normal’ they(alarmists) will cry the blues about the ‘drought’, when in fact, it will be normal….

  2. Brian H permalink
    January 17, 2014 6:16 am

    Will that be a normal extreme emergency or an extreme normal emergency? How can you tell?

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