Is UK September weather improving?

A friend called me this week to ask about a news story he’d heard on the radio. He’d been listening to a caller say that this warm September in the UK was really unusual and my friend didn’t believe so. I anecdotally remember the last 4-5 Septembers being nice weather (after a bad summer), but I also remember them being dire during the mid 90s (coinciding with waiting for the school bus). This has been more generally reported in the printed media.

So what do the records show? I downloaded regional monthly weather summaries from the Met Office and plotted up the following graphs (for un-anotated see below). I’ve highlighted what I consider to be the defining characteristics, i.e. a rise in mean air temperature of ~1°C for the UK, an increase in sunshine hours for England and a decrease in days with rain in England, all over the last few decades. A key limitation with these data is the Met Office haven’t updated them beyond August 2014.

September weather across the UK with a lowess smoother and 95% confidence bounds, (probably) key trends highlighted.

September weather across the UK with a lowess smoother and 95% confidence bounds, (probably) key trends highlighted.

And the un-marked plots:

September UK weather trends with a lowess smoother and 95% confidence bounds.

September UK weather trends with a lowess smoother and 95% confidence bounds.

Keen readers will also notice this is my first foray into using the ggplot2 package for R. I found it great for plotting the matrix of plots (facets in ggplot2 language) and was also much easier for adding smoothers with confidence bounds, compared to what I did to show snow cover trends on this post. However, I found altering text more of a faff than I am used to with base plotting. This may well be a perception thing.

The code for the above work is available on my git repo. This includes downloading files, cleaning files into a database, reading the database and plotting up the graphs. Please feel free to use it if you’d like to repeat this exercise for other months or time periods, etc..

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