Are We In For A Hot Summer?

[reef]

Another 1995 would be a treat, but even an average summer like 2005 or 1996 would seem good after the last two years! Even summers I thought at the time were poor like 1998, 2000 and 2002 were a lot better than 2007 or 2008 which were in another league entirely for their combination of frequent rain and lack of sustained warm, sunny periods.

I've often thought about a catalogue of UK summers since 1900, similar to the Bonacina snowfall catalogue: with the ratings being "Very Good", "Good", "Average", "Poor" and "Very Poor". Based not only on temperature but also sunshine, rainfall and the frequency and length of hot/dry/sunny spells. Looking at the data available, there are 5 that can definitely be called "Very Good" over the vast majority of the UK: 1911, 1947, 1959, 1976, 1995. 1989, 1983 and a couple in the early 30s are borderline Good/Very Good, and 2008, 1986, 1987 borderline Poor/Very Poor.

But then 2005 was very much an above average summer, just 8 were warmer since 1976. Summer 1996 also had temperatures not far off from 2008, just that it was percieved as better due to higher sunshine levels and less rainfall. The problem is, the last two years have been really quite average (temperature-wise). Take the summers of 1977-1987 for example, aside from 1982-84 they were absolutely appauling. Its really just another case of most people actually forgetting what an 'average' UK summer is like. If were to get a truely poor summer, many would be shocked.

I suspect that a summer with average temperatures would be seen in a much more positive light if it was also dry and sunny. The problem is that this combination is very rare indeed.

[Thundery wintry showers]

This is very true. It seems that in "high summer" (July/August) there is a strong tendency for cool spells to be associated with cloudy, wet Atlantic-driven westerly types, and fronts crossing at regular intervals, and for warm spells to be associated with blocking over and to the east of Britain (leading to hot dry sunny weather and occasional showers/storms) or ridging from the Azores High (leading to very dry weather, warm sunshine in the south but more cloud in the north).

Hence we get a strong positive correlation between temperatures and sunshine and an inverse correlation with rainfall.

This relationship is far less strong in June, when blocking to the north and west of Britain is still fairly common, especially early in the month. Thus we sometimes get dry and sunny but average to cool Junes with frequent northerly and north-westerly winds, or slack/cyclonic spells featuring a fair number of showers but also plenty of sunshine. So in June, temperatures, sunshine and rainfall only show weak relationships with each other.

I remember Summer 1996 well in Tyne & Wear. It is largely forgotten because of how remarkable the previous year's summer had been, but I have to say I really enjoyed that summer, as it had pretty much everything, and came out with well above average sunshine and mean maxima. There were some good thundery downpours too- 7 June 1996 for instance springs to mind- and August was quite a thundery month I believe.

[Jack Wales]

At the moment, I see little indication that the forthcoming summer should be any better than 2007 or 2008. With the ENSO being the main teleconnection we still appear to be embedded in the ENSO- (La Niña) type synoptics as we head towards summer, this is despite the fact that ENSO conditions have trended neutral over the last month or so.

There are of course a number of other factors that come into play but I’d like to see a synoptical shift from the current pattern to have any hope of a significantly different summer to that of the previous two years. Some of you may recall that last summer was played out to ENSO neutral conditions although having said that, the MEI peaked at around zero briefly in July (Nino 3.4) before trending negative again, this was not significant enough to alter the overriding signals at the time.

During the winter just gone the La Niña event was not quite as strong as the year previous and conditions appear to be trending neutral more readily this year. Currently the negative anomaly at Nino 3.4 is approximately 0.75C less than last year. Also if you look at the ENSO ensembles on the chart below, most of them appear to forecast a transition to weak El Niño conditions by the end of the summer period.

This is supported by the sub surface anomalies which also appear to be diminishing. An early prediction from me is that summer will start off in similar fashion to the previous two years with a cool and unsettled June and possibly July. However, 'if' the ENSO ensembles prove to be accurate then these conditions could help switch the presently embedded La Niña pattern to provide a significant improvement for the second half of summer and September.

[Thundery wintry showers]

June 2008 was widely perceived as a poor month but in fact much of southern, central and eastern Britain were drier and sunnier than average, and even Scotland, where it was wet, had close to average sunshine. A bit like May 2005, perceptions were clouded by the expectation for homogeneous warmth.

[Jack Wales]

Maybe so, although I distinctly remember a northerly mid month which delivered a ground frost to some parts of the Welsh Valleys, however when I predict that summer will start similarly to that of the previous two years, I don’t necessarily mean month for month, rather the general pattern for the season which on the whole was rather cool and unsettled.

[Yeti]

June 2008 was widely perceived as a poor month but in fact much of southern, central and eastern Britain were drier and sunnier than average, and even Scotland, where it was wet, had close to average sunshine. A bit like May 2005, perceptions were clouded by the expectation for homogeneous warmth.

People on here often describe how expectations have been raised with summers by quoting the past summer in particular, which featured average temperatures. What they often fail to do is look at the rainfall and sunshine, because last summer had something like 150% of the expected rainfall in July/August and below average sunshine, whilst still having average temps. I would love a summer with 18-22c and still to slightly breezy, sunny and dry conditions much more than 20-24c and wet. Sadly, this doesn't seem to happen for the reasons you explained earlier. Yet I imagine most people judge summers on their sunshine more than their absolute temperatures, for the simple fact that if the sun comes out when it's still in summer, you cannot help but feel warm enough.

[Jack Wales]

Indeed, high night-time minimas can make a month with rather cool maxima of 16C to 17C look 'average'. Similalrly a month of average precipitation can be made to look wet by a couple of heavy thunderstorms, personally I tend to look at the 'number' of wet days to decide if it has been a wet or dry period. It's tricky becasue everyone is different with varying degrees of preference for sun, heat and rain etc but overall Mr Data's scale is probably the best pointer as this takes most factors into account.

[Thundery wintry showers]

I would agree with you re. July and August which were indeed wet, and in the case of August very dull as well, but relatively warm due to high minima. There is little doubt that summer 2008 came out dull and wet overall, thanks to the phenomenally dull August.

But individually June doesn't fit that pattern as I recall it also being widely regarded on N-W as a poor month because temperatures were only average and it was quite unsettled- even though sunshine was above average over much of the country. I quoted May 2005 because the general perception then was of a dull cold wet month, yet it had close to average temperatures and rainfall and above average sunshine.

These days, a close to average spring is perceived as an extension of winter, and anything less than homogeneous warmth is classed as cold...

[J07]

I'm rather keen on a good summer for 2010, as I'll be home for some it it. The last summer I spent in the UK was, conveniently, 2006- so save up some more of that could you?

[William of Walworth]

It is very unlikerly that we get a hot summer. We are at present in a deep solar min and history clearly shows that really hot summers do not hapen in the U.K at the time of low sun spots. Of course they may well be some warm spells buit record breaking heat waves that we become used to are over. Further more to is most likerly any warm weather would occure in July rarther than August. in times of low sunspots August on average was a cooler summer month and most heat waves occure in June or July and they were quite rare. In the 17th century there were some hot summers before the major solar min took place but on average there were many more cooler summers. So this year this summer may well yet be just another average one or even a cool one.

This is too much of a deterministic and certainty-filled post in my opinion. I'm glad to see that no-one else in this thread seems to be agreeing that we're certain to get a indifferent/average/even poor summer or that a good one is near impossible, as Daniel seems to be close to claiming

Jack Wales is pessimistic, but even his predictions don't yet rule out a noticeably better summer than last year's and 2007's truly dire ones .....

i'm hoping for a cool wet summer. if you've ever lived in london you'll know why. london is a nightmare in the heat. hot tubes, trains, buses etc having said that i just love warm summer days in the countryside or by the coast, and hopefully this year i will be able to enjoy such

Trouble is I think the two halves of your wish are likely to be incompatible, bar some exceptionally dry airstreams. If we do get extended warm/hot periods, London (especially) does risk humidity and hard to cope with heat too. I'm not living in London anymore for now, but like several on here I'm fairly desparate for a good deal more sunshine and warmth than we had last year, and some extended dry and sunny periods. If I get my way at least you'll get your chance of some pleasant countryside walks at weekends, but I reckon it'll be at the cost of some tough City conditions ...

Edited April 7, 2009 by William of Walworth

[Yeti]

Trouble is I think the two halves of your wish are likely to be incompatible, bar some exceptionally dry airstreams. If we do get extended warm/hot periods, London (especially) does risk humidity and hard to cope with heat too. I'm not living in London anymore for now, but like several on here I'm fairly desparate for a good deal more sunshine and warmth than we had last year, and some extended dry and sunny periods. If I get my way at least you'll get your chance of some pleasant countryside walks at weekends, but I reckon it'll be at the cost of some tough City conditions ...

Lol, try Venice when it's 40c with 90% humidity and the whole city is running out of bottled water, so they put the prices up to 5 euros a bottle! Couple that with the stinking canals and trains with no air con; that's a nightmare!

Actually the hottest I've ever felt was on a train in Madrid last summer when it was 34c but the heating was trapped on full power (used in winter when it's bitterly cold). It was literally like a moving sauna, I've never felt anything like it and it must have been very dangerous to the elderly etc.

I can imagine the tube gets pretty bad in summer though - London's bad enough at any time of year in terms of rushing from place to place!

[morfius]

Actually the hottest I've ever felt was on a train in Madrid last summer when it was 34c but the heating was trapped on full power (used in winter when it's bitterly cold). It was literally like a moving sauna, I've never felt anything like it and it must have been very dangerous to the elderly etc.

I can imagine the tube gets pretty bad in summer though - London's bad enough at any time of year in terms of rushing from place to place!

They always seem to do that on the London buses - is it too much to ask for them to turn off the heating during mid summer!!

[J07]

Lol, try Venice when it's 40c with 90% humidity

Be assured that has never happened anywhere in the world, and certainly not in Venice. What you're claiming is a dewpoint of 38C and a dry bulb of 40C. Yeah, right!

People have a tendency to throw around high humidity values without properly thinking about it.

Venice's highest ever temperature was 37C. The dewpoint at that time would most likely not even be above 20C.

[Yeti]

Be assured that has never happened anywhere in the world, and certainly not in Venice. What you're claiming is a dewpoint of 38C and a dry bulb of 40C. Yeah, right!

People have a tendency to throw around high humidity values without properly thinking about it.

Venice's highest ever temperature was 37C. The dewpoint at that time would most likely not even be above 20C.

Artistic licence! It was certainly extremely hot and extremely humid - and I was there!

[J07]

No doubt it was hot, I doubt the humidity though.

A typical summer day in Flordia would reach a high of 33C with dewpoints about 24C. That gives a relative humidity of 63%, and yet still it feels very sticky.

When we are hot I think it's usually either high dry bulb temperatures that we feel, *or* high dewpoints. Any dewpoint over about 17C starts to feel sticky. The only exception to this rule is in special climates such as equatorials, or the Persian Gulf. In both those places you get a combination of high temperatures and high dewpoints. eg Singapore where you can get dewpoints in the mid to high 20s, and temperatures in the low 30s.

Even in the exceptionally hot and "humid" August 2003, I don't think London ever recorded dewpoints over 20C. The worst I remember seeing was a dry bulb of 34C and a dewpoint of 20C. That is probably pretty similar to what you had in Venice. No doubt it's very hot and uncomfortable for those of us brought up in cold climates, but it's not humid.

[SP1986]

I would actually lean on the side of thinking it will be a poor summer - I'm not certain of that and my only guide is the fact that everything already may be setting up in the wrong place - this can change though and the truth is that no one knows what summer will be like.

It's certainly not true that all summer in the solar minimum have been bad. Wasn't the summer of 1995 in a dip of the solar minimum. The solar minimum we have now maybe longer, but is not any more intense than ones weve seen over the last 20 years so this needs to be dispelled.

My opinion of a poor summer is part psychological, part expectant (due to previous poor summers), and part analytical of current patterns (of which there isn't much support that they can signal the summer pattern)

[summer blizzard]

I would actually lean on the side of thinking it will be a poor summer - I'm not certain of that and my only guide is the fact that everything already may be setting up in the wrong place - this can change though and the truth is that no one knows what summer will be like.

It's certainly not true that all summer in the solar minimum have been bad. Wasn't the summer of 1995 in a dip of the solar minimum. The solar minimum we have now maybe longer, but is not any more intense than ones weve seen over the last 20 years so this needs to be dispelled.

My opinion of a poor summer is part psychological, part expectant (due to previous poor summers), and part analytical of current patterns (of which there isn't much support that they can signal the summer pattern)

I'm actually going to disagree with you, i feel that this summer is probably going to be a milder version of 2005, however one thing i will be on the look out for is a dryer than average May.

[Yeti]

I would actually lean on the side of thinking it will be a poor summer - I'm not certain of that and my only guide is the fact that everything already may be setting up in the wrong place - this can change though and the truth is that no one knows what summer will be like.

It's certainly not true that all summer in the solar minimum have been bad. Wasn't the summer of 1995 in a dip of the solar minimum. The solar minimum we have now maybe longer, but is not any more intense than ones weve seen over the last 20 years so this needs to be dispelled.

My opinion of a poor summer is part psychological, part expectant (due to previous poor summers), and part analytical of current patterns (of which there isn't much support that they can signal the summer pattern)

Yes I think 1995 was, and remember some of the summers in the little ice age were some of the hottest ever.

[damianslaw]

Interesting observation how the past two summers saw some very warm (record warm) weather of sustained longevity occuring in the preceeding spring i.e. Arpil 2007 and first half of May 2008, don't want to pattern match but perhaps an 'average' spring without any sustained near/record warmth this spring will be a good omen for summer.. who knows..

[SP1986]

If we got a warm spring dominated by high pressure over the continent then I believe that scenario could lead to a hot summer. Otherwise 2003 is a more complex pattern whereby Spring was dominated by HP cells over the UK moving in from the Azores. Moving into June the continental high popped up so we got some hot weather through the remainder of the summer.

This year there is a small possibility that the Azores and European high could join resulting in a warm, humid, and at times wet summer.

[reef]

Theres really little link between what the weather does in Spring and what the following summer turns out like. Its just the same as trying to predict what winter will be like based on what Autumn does. Theres no link at all.

Take 2002 and 2003 for example. Both years saw very warm springs with almost identical means, the synoptics were even quite similar, yet the summers were vastly different.

2002:

March: 7.6C

April: 9.3C

May: 11.8C

Summer: 15.8C

2003:

March: 7.5C

April: 9.6C

May: 12.1C

Summer: 17.3C

Whether spring is mild or cold, wet or dry, blocked or unblocked, summer will do what it does and theres no proven link.

Edited April 8, 2009 by reef

[Schnee]

I'm dreading the summer. In 2006 my bedroom got to 40ºc and remained in the 30's till late October. I do not want to experience that again for a while!!!!!

[Derp Patrol]

Haha, that is probably the only downpoint of summer, it is great during the day if you're like me and love soaring temps into the 30s, but night time temps in the low-mid 20s are very unpleasant, and even with the window open it is very hard to sleep

[Thundery wintry showers]

I mentioned earlier a tentative link mentioned in one of Philip Eden's books about how the hottest summers are often (though not always- e.g. see 1975!) preceded by notable spring hot spells. This was certainly the case in 1976, 1989, 1990, 1995 and 2003.

[Wales123098]

Haha, that is probably the only downpoint of summer, it is great during the day if you're like me and love soaring temps into the 30s, but night time temps in the low-mid 20s are very unpleasant, and even with the window open it is very hard to sleep

In 2006 we thought we were going to have more summers like this and we strugled to sleep so after a week of the hot we had airconditioning installed in my house throughout, we havent used it since

Edited April 9, 2009 by Wales123098