Plenty of sunshine across the southeast of the country at the moment, and for large parts of Europe. These are the hourly sunshine totals for 12-13 UTC today (fig 1), it’s a shame that Ireland, the Netherlands, Scandinavia and Iberia don’t include this hourly data in their weather reports.
I think I can say without a doubt that today has been the warmest day so far this year, at least in our part of south Devon. It’s not been particularly high, maybe just scraped a 22 or a 23°C this afternoon in the back garden, but it’s enough (fig 2). Personally speaking, this year Spring seems to have been a long time coming.
Certainly the solar radiation has been high (fig 3), and so must the UV, but unfortunately the SYNOP reports don’t include that.
Just what the Doctor ordered
Not only did the southeast get the warmest day yesterday (which is more that can be said down here in the southwest) they also got a good long spell of moderate rain, which must have come as welcome relief to the farms and gardens that have been crying out for it over the last six weeks or so. For a long time I thought that the rain gauge of the AWS in St James Park must have been faulty or perhaps full of pigeon excrement.
The estimates that I make from radar images were a little high, for example I estimated a 18-06 total for Wattisham of 21.8 mm and in reality they recorded 20.2 mm [06-06]. The coast of Kent seems to have escaped most of yesterday’s rain though.
Wattisham, as well as being the wettest place yesterday with 20.2 mm in the reported SYNOP’s (fig 3), also managed second warmest with 25.2°C (fig 4).
I still suspect that there is some kind of geothermal energy going on in close proximity to the Stevenson screen at Broadness, because yet again they were the warmest station in WMO block #03.
Despite the warmth in the southeast, I reckon the best day yesterday was in the far north or west albeit considerably fresher, Kirkwall reported 12.6 hours of sunshine, and stations in Ireland added more sunshine to their already high totals so far for May (fig 5).
I thought that I would investigate and find out exactly what climatologically is the sunniest month of the year using monthly sunshine data from the Met Office. The gridded sunshine record only started in 1929, but I’ve been reliably informed by someone in the know at the Met Office, that plans are well advanced to extend this (along with the rainfall and temperature series), back to at least the start of the 20th century, which I applaud, although in my opinion it’s a long way overdue. The add-on to my application looks not only at sunshine, but rainfall and temperature too, and for any region within the United Kingdom. The pie chart I’ve include is for England & Wales (fig 1), and reveals, surprisingly to many I bet, that May is climatologically the sunniest month of the year in 35.2% of years since 1929, followed by June in 31.8% of years, and July in 19.3% of years.
Figure 1 – Data courtesy of the Met office
Also rather surprisingly, it can happen that in some years April is the sunniest month. According to my application that’s occurred five times, in 1945, 1954, 2002, 2007 and 2011, so three times in the last 15 years. There’s always a chance that I’ve made an error let me know if I have.
The sunniest month in the entire England and Wales record was the July of 2006 with 287.6 hours of sunshine (fig 2). The sunniest month in the famous summer of 1976 was also a July with 251.5 hours of sunshine, but ranked only 13th in the list of sunniest months in a year.
Figure 2 – Data courtesy of the Met Office
What was the sunniest May in the UK? That of course depends on where you live, so using the regional gridded sunshine data series from the Met Office that started in 1929 here is a map of the sunniest May for each of the nine individual regions, and for the whole series in a horizontal bar chart (fig 1). May is climatologically the sunniest month of the year in the UK, but more of that in an upcoming post, and by the look of it, the May of 1989 was the sunniest in nine of the seventeen regions, including the UK and England and Wales, if the gridded sunshine values are anything to by.
Figure 1 – Data and map courtesy of the Met Office.
The 1989 record certainly is in no danger of being broken in the southeast this year, but it’s certainly could in Northern Ireland and the west of Scotland, where they’ve got off to a flying start (fig 2).
It’s been a wonderfully sunny start to May in Northern Ireland, with Aldergrove recording 133.3 hours of sunshine in the first 10 days of the month. They have now jumped ahead of the ‘Sunshine Island’ of Tiree as the sunniest place in western Europe this month, with Alicante now close behind in fifth position (fig 1). In stark contrast, the dearth of sunshine in the southeast is quite noticeable in the chart, with just a measly 33.7 hours of sunshine so far this month at Wattisham.
Figure 1 – The AWS at Tiree courtesy of the Met Office & Ordnance Survey
Tiree is the place to go if you want to top up your tan this month (fig 2). In the first eight days they’ve already got a ton up with 113.2 hours of sunshine, which is a daily average of 14.1 hours, and almost 90% of the maximum possible. Yesterday at Tiree, they cracked the 15 hours of sunshine in a single day mark, and will no doubt do it again today.
Not far behind them are the two sunshine stations in Northern Ireland, followed by Prestwick on the Ayrshire coast (fig 3). I find it amazing how nature always tries to redress the balance in these things, after such a cloudy month in this part of the world last month.
To put it into perspective, the sunshine totals so far this month in Western Scotland are higher than anywhere I can see in the western Mediterranean, with Alicante the only station to have recorded more than 100 hours this month (fig 4). Having said that the potential daily sunshine is higher the further north you go at this time of year, which does help a bit.
***Updated 10th May 2017 ***
Due to the unprecedented numbers that have been looking at this article, I thought that any new readers would like to see if Tiree did actually get 15 hours of sunshine yesterday, not quite they got 13.7 hours, nevertheless there are still currently the sunniest place this month in Western Europe with 126.9 hours of sunshine in just nine days (fig 5), that’s an average of 14.1 hours per day. Sadly today, there are cloudy skies over Tiree, but it was good while it lasted.
A reversal of fortunes in the sunshine league in the last seven days across the British Isles, with the west and north of Scotland now the sunniest places to be (fig 1), rather than the Channel Isles and the south as it was for most of April.
Apologies about the title of this blog, which has nothing to do with either its content, or Star Wars for that matter, just the date on which it was published.
The sunniest place on average in the UK in the period between 1981 and 2010 is Shanklin on the Isle of Wight with 201.4 hours. In fact most of the climate stations in the top 17 can be found on the English Channel coast somewhere. On the southwest peninsula the fall off in sunshine the further away from the coast you are looks to be around 10%. The Met Office provide these 1981-2010 average in their DataPoint web service and are not neither straightforward to download or to parse, because they’re all in XML format and come as individual files for almost 300 locations. The things I have to go through for a climate story.
I contacted the Met Office at Jersey yesterday and asked them what their record highest April sunshine total and got this tweet back.
I make their total for the same period 249.5 hours, yesterday they had another 2.5 hours taking them up to 252.0 hours. I’ve tweeted the Met Office at Jersey and asked them to check their total, but so far have had no response. As far as I can see I’ve done the maths correctly, and my old maths teacher Mr Brightmoor I’m sure would have been proud of me. The 1981-2010 average for Jersey is 196.5 hours in April, so that makes the latest anomaly just over 28% above the average.
A very sunny month especially across more southern and eastern areas of both Scotland, Wales and England, but always cloudier the further northwest that you went, and more generally over Ireland (fig 1). The sunshine figures are for some reason always more reliably reported in a SYNOP report from a AWS than are rainfall totals, as you can see from the Rx column (fig 2) most stations are at 100%. Jersey is still miles out in front this month, with over 240 hours of sunshine, being an Island in a relatively cold English Channel does help a bit in that department. There are several other chasing stations who also might crack the 200 hour barrier this month, and today might help in that regard at Camborne.
These sunshine totals are high but they don’t look high enough to beat the April of 2015 which was exceptionally sunny across the country (fig 3). ‘Sunniest since 2015’ doesn’t make much of a headline I’m afraid.
Figure 3 – Data courtesy of the Met Office
The Met Office do provide monthly climate statistics for Jersey, so it looks like this April they are currently around 122% of the average, with four days left of the month. I’ve Tweeted the Jersey Met Office to try and find out if they know what the sunniest April on record there, hopefully they will reply, and not by Tweeting ‘yes we do but we are not telling you’.
Figure 4 – Courtesy of the Met Office
Jersey have taken over at the top of the sunshine league this April, with almost 9 hours of sunshine each day for the first 20 days of the month. Their total of 178.6 hours so far is I estimate 66.1% of the possible maximum total. It’s not been sunny everywhere across the British Isles, but without detailed climate statistics to produce anomaly values it’s impossible to be precise, but as usual, it seems to have been duller the further west and north that you are so far this month (fig 2).