Extreme Monthly Rainfall Trends in the UK

[BornFromTheVoid]

xmetman posted a thread about daily rainfall stats in the climate area a short while ago, which sparked my interest. Here's the thread http://forum.netweather.tv/topic/79384-are-extreme-rainfall-events-more-common-in-the-uk/

 

I downloaded the monthly UK precipitation data from 1910, and posted a little analysis. Today I had a look at the months on that record that exceeded 2 standard deviations (σ) above the 1910-2012 averages for each month.

Below is a graph showing the numbers of months exceeding 2 standard deviations (σ) above average rainfall in each year.

 

 

Judging by the chart above, it seems that 2σ monthly rainfall totals have gone from occurring once every 4.3 years on average to once every 2 years.

 

The majority of this increase has occurred in the Winter half of the year (October to March)

 

 

Here, the likelihood of achieving a 2σ month during the winter half of the year has gone from roughly once every 25 years to once every 3.6 years

 

Summer (April to September) shows almost no trend at all.

 

 

 

Anywho, I thought these results turned out quite interesting. This year has started off continuing the trend, and if February end up joining the list of 2σ months, it will be the first winter with 2 such months.

 

Feel free to point out mistakes and make suggestions!