East Anglia tops the Summer Index for 2017

Figure 1

Of all the regions in the UK, East Anglia has the highest Summer Index for 2017, with an index of +10 (fig 1). Western Scotland came bottom of the table with an SI of -11, mainly because the summer was so dull. The UK as a whole returned a disappointing SI of -1, which was lower than the +10 of 2016 (fig 2). Don’t forget the maximum SI a summer can achieve is 48 which it did in 1976. The last really good summer across the UK as a whole according to the SI at any rate, was 2013, with an SI of 32 (fig 2). If you’re new to what the Summer Index and how it’s calculated you can read an article that fully describes how it’s calculated here.

Figure 2

The scatter graph for mean maximum temperature and total rainfall indicate that although the summer had been a little warmer than usual, it was also a lot wetter than average too (fig 3).

Figure 3

The scatter graph of maximum temperature and total sunshine indicate that the summer has been slightly duller than average (fig 4).

Figure 4

Let me know if you notice anything wrong with the various terciles and quintiles, I’m far from perfect.

An extended summer index


Recently I developed an application that uses the Met Office regional and national gridded data back to 1929. I would have used the whole series but sunshine data has only been gridded back to 1929. Anyway my first stab was to list the summer index using the months June, July and August, the ‘meteorological’ summer and wrote this article about it. Now that summer 2016 is finally and fitfully coming to an end I thought I would extend the application to generate and index for the extended summer May through to September.

1976 loses out to 1959

As you can see from the above chart the results for the extended summer are quite different from those of just June, July and August, some summers like that of 1976 lose their #1 rank and drop to #12, whilst the summer of 1959 jumps up to the #1 slot as the best summers in the UK since at least 1929.

The reason why 1976 slipped so much was that May and September in 1976 were both rather wet and dull over the UK so the index is lower, whilst the May and September of 1959 were much drier than the June and July, and in 1959 sunshine was never in short supply during any of the five months of the extended summer. Below is a ranked list of both highest and lowest summer indices for the UK as a whole, the maximum score is 80 and the minimum score -80 for the extended summer, rather than 48 and -48 for the meteorological summer.


As you can see from the table below the worst summer in the UK since 1929 in both the meteorological and the extended forms was 1954, with an index of -64. The summer of 2016 as you can see is currently joint #17, but only comprises 4 out of the 5 months of the extended summer, so I’ll keep you posted when the September data eventually arrives to see how it performed.


Regional Index

Regionally in 1959 northeast England and the Midlands came out top with an index of 72 out of 80. Scotland didn’t fare quite as well but the indices there were still positive and still relatively high.


In 1976 southeast England had the highest summer index of 48, but Scotland and northern Ireland didn’t score too well.best-extended-mjjas-summer-index-1976

At a glance

Finally here are a couple of charts that show you at a glance the last 87 summers and how they compared as regards temperature versus rainfall, and temperature versus sunshine.


As you can see 2006 was warmer than 1959 but not drier or sunnier. 1989 was a little sunnier than 1959 but cooler and a little wetter.

In Conclusion

I am now glad that I subscribed to the Weather magazine and found these old articles concerning the summer index. It’s a quick and easy way of comparing summers of the past and hopefully I can do the same for winters but that will be a lot trickier.

There are 17 different national and regional areas within the 1910 data series, so it’s not really possible to display all of them in this one blog. Let me know if you would like me to generate you a regional or national table and I’ll email it to you. Of course please let me know if you spot a problem with my maths, after all I have been an ex-metman for almost five years now.

Summer 2016 – best in East Anglia worst in Scotland


I have just downloaded the gridded 1910 data series from the Met Office for August so that I can have a look at the 2016 summer index across the country. I require that sunshine, rainfall and temperature gridded data so I can calculate the monthly terciles and quintiles values that are used to calculate the summer index. The summer is of course the meteorological summer and consists of the months June, July and August. The table below is the summer index for the whole of the UK, and as you can see summer 2016 index was +10 which is above average and much better than last year, but comes only joint 19th best since 1929.

UK Summer [JJA] Index 1929 - 2016
UK Summer [JJA] Index 1929 – 2016

The picture is much better when you look at the regional summer indices that I’ve also calculated and ranked. East Anglia comes top with an index of +25 just ahead of southern England with +20. Incidentally, in East Anglia summer 2016 was also the best summer index since 1995. No region in Scotland fared particularly well this summer with summer indices of around average (remember the best summer scores 48 and the worst summer -48 using the summer index formulae). You can find more details about the summer index in an earlier article I wrote earlier this year.

Best Summer Index [JJA] in 2016
Best Summer Index [JJA] in 2016