What is it about halloween?


Last year you’ll remember that the temperature at Trawsgoed in Ceredigion, Wales on the 1st of November 2015 – all Hallows’ day – reached 22.4°C and set a new record for the warmest November day in the UK. Similarly 2016 seems to be following suit, because the maximum temperature today on the 31st of October 2016 – all Hallows’ eve – and spookily again at Trawsgoed reached 22.2°C.  Although this wasn’t an October record it got me to thinking when was the warmest 31st of October up until now? To be honest I don’t have the exact answer, but with the help of the Central England Temperature [CET] series I thought that I could make a very good educated guess. I already have the code (now there’s a surprise) to list the CET for any particular day of the year. You select a particular day and it lists the warmest or coldest maximum, mean or minimum temperatures for that particular day back to 1878, or for means back to 1772. And here’s the output from that program for the 31st of October:-


Warmest 31 October in Central England (1878-2015)

So it looks like the Halloween of 2014 with a maximum CET of 20.6°C looks a pretty safe bet. The maximum anomaly for that Halloween was a massive +8.3°C, the second warmest on record occurred on the 31st of October 2009 with a maximum of 16.6°, a full 4°C lower. So what did the chart for Halloween 2014 look like?


1800 UTC on 31 October 2014

As you can see a broad SW’ly warm sector with fresh southerly winds.

Courtesy of the Met Office

Courtesy of the Met Office

Here are the plotted 0600 to 1800 UTC maximum temperatures for Halloween 2014.


Maximum Temperature [06-18] on 31 October 2014

And as you can see our old favourite hot-spot of Gravesend was the warmest place again with a maximum of 23.6°C. I’m sure I heard Louise Lear (5.57PM) say that the 22.2°C maximum today at Trawsgoed made it the “warmest Halloween on record”, I also heard her at 6.27PM when she had changed that ever so slightly to the “warmest Halloween in West Wales” (which is probably correct), I think she might like to take a look at Halloween 2014.


Maximum Temperature [06-18] on 31 October 2014

And just for the record these are the warmest places today across the UK for you to compare.


June 2016 – Temperatures across the UK

Here’s a list of the warmest stations by day [06-18] from across the British Isles as reported in their SYNOP observations during the month of June 2016. Unfortunately I still haven’t written the code that’ll allow me to produce an anomaly for each station, so mean temperatures will have to do for now. The remarkable thing is how after a very cool start, the stations in the southeast of England just managed to bounce back and pinch the top two spots in the warmest by day. As you can see the mean maximum temperature [06-18] was almost 21°C  in central London. Exeter came in at joint #9 but I did miss a number of 1800 UTC observations from the station during the month.

Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

At the other end of the scale, islands around the north and west of Scotland were coolest (the lowest [06-18] maxima) as you would expect at this time of year, along with a number of coastal stations down the east coast of both Scotland and England.

Lowest Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

Lowest Maximum Temperature 0600 – 1800 UTC 1 June 2016 – 1 July 2016

The southeast didn’t manage to make the warmest place in June which went to Glasgow with 27.3°C on the 6th of June –  do you remember that warm spell at the start of June?

Highest Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

Highest Maximum Temperature 0600 – 1800 UTC 1 June 2016 – 1 July 2016

The night of the 22/23rd of June was very mild with overnight [18-06] minimum temperatures in London no lower than 18°C.

Highest Minimum Temperature 1800 - 0600 UTC 1 June 2016 - 1 July 2016

Highest Minimum Temperature 1800 – 0600 UTC 1 June 2016 – 1 July 2016

The latest climate statistics

I’ve written some additional code for my SYNOP application to generate images of various climate statistics derived from the SYNOP reports that I download from the internet. As a starter, I thought that I would list the thirty warmest, coldest, wettest and sunniest SYNOP stations from WMO block #03, which comprises over 150 stations across the United Kingdom and Irish Republic. I’ll generate and then upload the images in my application to my website, and then display the small images in widgets down the sidebar, as you will most likely have noticed. To be honest it would probably be more efficient if I wrote a bespoke widget that took a CSV file of places and values and displayed them in a ranked tabulated list, but for the moment this solution will have to do, because I have no experience of writing WordPress widgets in Javascript and PHP. All I’ve got to do now is to remember to run the code each day to update the images!

Wettest place

Warmest Place

Coldest Place

Sunniest Place

Possibly the warmest May on record?

I have read reports that this month will end up being the warmest May on record thanks to a heat wave in the last 10 days of the month. Going by the latest provisional values of the Central England Temperature [CET] series, so far this month (up until the 20th) that looks a total impossibility. A quick bit of calculation to see just how hot the last 11 days of the month would have to be to beat May 1833 reveals that the daily mean would have to exceed 20.1°C for every remaining day of the month. The people who are making these predictions obviously didn’t realise just how exceptionally warm May 1833 was, +4.64°C above the long-term average. Currently May 2016 is tracking just inside the top twenty warmest at #19, with a mean anomaly of +1.97°C, which in itself is very high. Even if the short cold spell between the 14-16th hadn’t occurred it still wouldn’t have been anywhere close to beating 1833.

Daily Central England Temperature Warmest start to a May 1772 - 2016

Daily Central England Temperature Warmest start to a May 1772 – 2016

Remember you can keep an eye on the latest CET values in these special static pages dedicated to them.