General summer chat

[damianslaw]

Hoping the core summer period late June to mid August is far drier than last year. 

[Methuselah]

 reef That's true, reef; but my memories of it are biased by the fact two outright stinkers preceded it! 

[Cheshire Freeze]

 damianslaw I don’t. Unless the air is dry too rather than that humid, hot crap we’ve had to endure in recent years.

Would much prefer a situation with HP slightly to our west and a gentle NW’ly flow if it has to be dry.

[damianslaw]

 LetItSnow!   Interesting to note the very warm.summers of 76, 95 and to a lesser extent 2018 came on the back of very dry springs (2018 mid April onwards), feel a dry spring helps aid heat in the summer. Not sure how dry spring 2022 was though.There are probably plenty examples of dry springs followed by wet summers though!

Edited March 8 by damianslaw

[reef]

 damianslaw It was the third driest Spring since 1980 for us. 23.0mm in March, just 4.0mm in April and 37.8mm in May.

[damianslaw]

 reef There is a strong correlation then.

[stainesbloke]

 Cheshire Freeze Some nice southerly breezes bringing plentiful warm sunshine and thundery outbreaks from time to time, please. Little Atlantic s.hyte for a couple of months would be good after last July

Edited March 8 by stainesbloke

[damianslaw]

 Cheshire Freeze Agree dry southerly/se airstreams are not my cup of tea, high pressure overhead or to the north west and north or north east far better, less humid, with cool nights. 

[Cheshire Freeze]

 damianslaw This is the thing. In peak summer you don’t need 30C+ temperatures for it to feel hot. The sun just needs to be out.

21-24C in June and July under sunny skies feels very much like summer.

[LetItSnow!]

 damianslaw Spring 2022 was dry. April in particular was very dry. I think down here the second-half of March was mostly rainless and a lot of April had barely any rain, but May was actually rather wet. May 2022 was a strange month in that there was no protracted or notable warmth and it wasn't that sunny but it was consistently mild with mild nights. 

A flick through the history books do show that while there are some dry springs before bad summers, a lot springs before bad summers do seem to be average to wet. I did find the likes of 1956 and 1974 there though. 

[Metwatch]

14 hours ago, Addicks Fan 1981 said:

it seems like 1973 is the strongest analogue of the lot for summer of this year with the combination of el niño into la niña

What was the Chinese animal for 1973, perhaps also the pig like in 2007 and 2019?

 

38 minutes ago, Cheshire Freeze said:

21-24C in June and July under sunny skies feels very much like summer.

Don't really get those sort of temperatures in summer without much cumulus building in and turning it cloudier through the afternoon, Perfect temperature for April to May though with the lower humidity High 20s would be more like it in summer with cooler nights and not too humid, so a nice diurnal range to cool down. Overhead high pressure rather than southerly plumes needed for that.

Edited March 8 by Metwatch

[B87]

 Cheshire Freeze those temps would be below average to average in summer here. Summers with 21-22c averages in July tend to be absolute rubbish to 2007, 2011, 2012 levels.

Edited March 8 by B87

[danm]

3 minutes ago, B87 said:

those temps would be below average to average in summer here. Summers with 21-22c averages in July tend to be absolute rubbish to 2007, 2011, 2012 levels.

Yep - in peak Summer down here, 21c and below I'd class as disappointing, even if it's sunny. 22c/23c is OK, 24c is about average, 25c-28c is that perfect middle ground of warm to very warm but not too hot. 29c/30c and upwards is classed as hot. 

[Frigid]

The disparity between north and south climates is quite astonishing, especially in summer. The 10 year average max for Heathrow is around 25C for July. Up here it's more like 21C, though we do get the odd month where it does average 25C (July 2018). Last July, the average max for Manchester Airport was 18.9C. July 2020 saw 18.4C. Those figures would be near impossible down south. I'd class anything below 20C as quite cool, and below 19C as very cool for the given climate. Anything above 22C would be warm, and 23C very warm. 

[Addicks Fan 1981]

@Metwatchthe Chinese animal in 1973 was the ox FYI.   

[damianslaw]

 Frigid Westerly airstreams with cloud and rain tend to deliver maxes anywhere between 18 and 22 degrees here... even in the height of summer. 

[danm]

1 hour ago, Frigid said:

The disparity between north and south climates is quite astonishing, especially in summer. The 10 year average max for Heathrow is around 25C for July. Up here it's more like 21C, though we do get the odd month where it does average 25C (July 2018). Last July, the average max for Manchester Airport was 18.9C. July 2020 saw 18.4C. Those figures would be near impossible down south. I'd class anything below 20C as quite cool, and below 19C as very cool for the given climate. Anything above 22C would be warm, and 23C very warm. 

Quite the difference, July 2020 had an average max here of 23.8c, 5.4c higher. July 2023 here was 22.8c.

The last Summer month we had in London that didn't exceed 20c as an average max was June 2012 - one of the worst Summer months I can ever remember - and that was 19.3c.

Edited March 8 by danm

[B87]

 danm It is an extreme event for London to get a sub 20c summer month. Before June 2012, the last occurrence was June 1998 (19.9c), and before that June 1991 (17.8c, the coldest June on record).

It is almost unheard of for that to occur in July or August. In the entire Heathrow record, the following months achieved it:

July 1980: 19.7c

July 1965: 19.3c

August 1963: 19.8c

August 1956: 18.8c

July 1954: 19.2c

August 1954: 19.8c

July 1954 and August 1956 are the coldest of those months on record at Heathrow. Summer 1954 was absolutely catastrophic, even compared to the other horror shows of the 50s and 60s.

 

Edited March 8 by B87

[stainesbloke]

 B87 Indeed. 24°C wouldn’t be too bad, but only if sunny. 
The trouble with these cool summer months is they are rarely sunny. A high pressure sat to the west giving us a northwesterly flow is usually a recipe for explosive infill with clearances appearing at 7pm. No thanks. 

[B87]

 stainesbloke Dry, sunny and cool summer months are very rare here. 

Going through the Heathrow data:

June 1962

July 1964

August 1964

June 1969

July 1977

August 1981

July 1985

August 1993

August 2007

Remove the dry requirement and you can add a few extra months, eg June 2008 or August 2014, but the 3 listed above seem to be it for sunny and cool Julys.

Edited March 8 by B87

[raz.org.rain]

 B87 to be honest even as a northerner, 21°c-24°c would be the lower end of expected mild weather for me.

Edited March 8 by raz.org.rain

[Metwatch]

Perhaps a crumb of comfort for the many seeking something warmer and drier. Getting some 2018 vibes with what Simon Lee posted above; sacrifice a poor first half of spring, for a nicer May - July period maybe given the stratopshere behavior of recent and forecasts.

Skilful predictions of the Summer North Atlantic Oscillation

WWW.NATURE.COM

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The Summer North Atlantic Oscillation responds sensitively to an anomalous strength of the stratospheric polar vortex in spring, which can be exploited for seasonal predictions, according to large-ensemble...

Edited March 8 by Metwatch

[Frigid]

 B87 June 2012 saw an average max of 16.6C.. and in 91, a max of only 15.6C! Most May's are warmer than that these days. I suspect 1971/72 to be even lower. 

[danm]

1 hour ago, B87 said:

It is an extreme event for London to get a sub 20c summer month. Before June 2012, the last occurrence was June 1998 (19.9c), and before that June 1991 (17.8c, the coldest June on record).

Looking back at June 1991 - it was a shocker! Very cool and quite wet. The rest of that Summer was better but lacked much proper heat. 30c wasn’t breached in London.

When you look back at many of the cool Summers of the 80s it’s quite striking how often in those days you would get Summers that wouldn’t hit 30c+. 

That is a rarity these days. I think the last Summer here not to hit 30c was 2007 or 2008 and that was an anomaly. Even poor Summers such as 2021 still have a hot spell with a few days hitting 30c+. It does seem that since about the mid 90s onwards, pretty much every Summer barring a couple of exceptions breach that 30c mark whereas before that it was much more common not to. 

Edited March 8 by danm

[WYorksWeather]

I did some checking a while ago. The 'old' benchmark for an average summer (roughly 50th percentile) was 32C (or more commonly in those days, 90F). That's the absolute annual maximum, anywhere in the UK, and was typically reached about half of all years.

Admittedly this is a bit of a short time horizon, but in the last 10 years we've seen 5 years reach 35C or higher, so you could argue that the new standard for a hotter than average annual maximum is 35C. Which is crazy, when you think that such an occurrence happened less than once a decade in the 20th century (nine years - 1906, 1911, 1923, 1932, 1948, 1957, 1976, 1990 and 1995).

For those interested in overall UK annual maxima, Trevor Harley's page here is useful and is where I sourced these stats from:

Hottest day of each year from 1900

WWW.TREVORHARLEY.COM