Moans, ramps and banter

[danm]

Just now, B87 said:

It was a few hours below the average. It's only really because of June that it got anywhere near the average.

Heathrow was 3 hours shy of the 1991-2020 average. I think we can probably call it an average year for sunshine! 

[B87]

 danm The Met Office historic data page and Meteociel for daily values.

The sunshine needs to be corrected by about 6% in December, up to 14% in June. In April the true value is 1.1x the raw value.

[danm]

 B87 an ok thanks. The thing is, on the met office and metociel pages they seem to have the raw sunshine totals, not the corrected values. Where do we see the corrected values? 

[B87]

 danm I got the 2006-2020 corrected values from the Met Office, then looked at the average correction for each month in that time period.

The method I use now probably isn't 100% accurate, but it always matches up with the monthly sunshine maps that use the true values.

To get a good idea of the true value, multiply the raw values by the following numbers (other stations might have different conversion factors):

Jan: 1.076

Feb: 1.080

Mar: 1.080

Apr: 1.090

May: 1.124

Jun: 1.141

Jul: 1.129

Aug: 1.122

Sep: 1.099

Oct: 1.091

Nov: 1.077

Dec: 1.068

CS0044355 Heathrow Monthly Sun Hours 2006-2020 (002) (1)-1.xlsx

[CryoraptorA303]

 B87 Don't forget May and the Autumn, the latter was surprisingly sunny for the SE:

I suppose it's not that surprising, only March, July and December were seriously dull last year, and December barely even matters. April was a tad dull, the rest were either average overall or sunny. This year February, March and now April have all been dull, April especially so although it doesn't feel like it's been as dull or a duller month than March was, but the stats don't lie.

Annual sunshine is a bit of a screwy stat, you could have January-May and October-December all dull, but if two out of four from June-September were significantly sunnier than average and the other two not below then the year would overall be sunny despite it being very dull per capita. Kind of like life expectancy stats for pre-modern eras I suppose where they don't tell the full story.

 

[danm]

 B87 thanks! Why does the Met Office not publicly display the corrected values? Or do they up to a certain year? 

[B87]

 CryoraptorA303 December was notable as it was the 3rd dullest on record at Heathrow, after 1969 and 2010.

May wasn't that notably sunny, it saw 221 hours vs the average of 208 hours. A full day of sunshine would account for that.

If June hadn't been very sunny, the year would have seen around 1590 hours of sun, which would have made it one of the duller years since 1990.

It looks highly unlikely that we will claw back the 140ish hour deficit that we will be on by the end of April, by the end of the year, with the first half of May looking unsettled as well, we could have a 200 hour deficit by the time summer starts.

 danm I only got those 2006-2020 true values as I put in a FoI request to get them.

[TwisterGirl81]

Can I ask what you guys mean about corrected values? Are the sunshine figures not accurate and under calculated on Metciel?

[Addicks Fan 1981]

 CryoraptorA303 the year of 2007 was actually sunnier than average too albeit to the skin of its teeth.  I think the second warmest april and the benign autum of that year counteracted the infamous washout of summer of 2007.   I would suggest you watch Gavs Weather Vids on summer 2007, it was probably the joker in the pack summer of the noughties decade and heralded a climate change hiatus until July 2013 came round.    

[B87]

 TwisterGirl81 The values on the Met Office historic data page, and Meteociel, are the raw values (at Heathrow at least, probably the same for most locations). The true values are the ones used to create the monthly anomaly and totals maps.

[TwisterGirl81]

 B87 the first half of May last year wasn’t reliably sunny but we still reached 247.8 hours, makes you wonder what a truly sunny month could get to? 350 hours? Has it ever happened in the uk? I know we’ve had some rare 300+ months

[B87]

 Addicks Fan 1981 Between 1991-2023, 2007 was actually the 11th sunniest year with 1703.5 hours. Helped by a very sunny March/April, a slightly sunnier than average August, November and December.

At Heathrow, April 2007 absolutely demolished April 2021 in sunshine totals.

Edited April 24 by B87

[danm]

 B87 strange why they don’t publish the true, corrected values…..

[CryoraptorA303]

1 minute ago, B87 said:

December was notable as it was the 3rd dullest on record at Heathrow, after 1969 and 2010.

Indeed, it was even duller than 2021 and that seemed like the bottom of the barrel.

2 minutes ago, B87 said:

It looks highly unlikely that we will claw back the 140ish hour deficit that we will be on by the end of April, by the end of the year, with the first half of May looking unsettled as well, we could have a 200 hour deficit by the time summer starts.

Of course, that depends. Unsettled doesn't necessarily mean totally Sunless as it depends on the exact synoptics but we will have to see.

It's quite possible for a 200 hour deficit to be made up over the rest of the year from mid-May. Two of the summer months being sunny would be well on the way to closing the gap, and one of them being very sunny along with another sunny overall might outright close it. Even September still has at least 226 hours to potentially give (1911, the sunniest on record for Heathrow's region), although the sunniest in recent times is 2003 with 194 hours, which could still close the gap. If the rest of the autumn months chipped in with what they can give then we could even still end up with sunnier than average.

[B87]

 TwisterGirl81 350 hours in definitely possible on the south coast, and has happened before in hot/sunny summers.

Heathrow has seen 3 months with more than 300 hours of sun. May 2020 (330 hours), May 1989 (310 hours), and July 2006 (302 hours). We are due a 300 hour June or August. The sunniest June was 294 hours in 1975, while the sunniest August was 295 hours in 1995.

[Addicks Fan 1981]

 TwisterGirl81 was summer 2007 one of your horror summers you can remember? It certainly was a notorious season alright, yet the summer overall had average amounts of sunshine and temperatures close to normal too, nevertheless though it was still a washout and coincided with rihanna featuring jay z with umbrella being number one in the charts for ages.     

[CryoraptorA303]

9 minutes ago, Addicks Fan 1981 said:

I think the second warmest april and the benign autum of that year counteracted the infamous washout of summer of 2007

Definitely, and as mentioned August was a significant improvement on the preceding two months as it often tends to be in the infamous summers, so overall sunnier than average.

The hypothetical "dull January-May - sunny to varying degrees June-September - dull October-December" screwy case that I mentioned must've happened for real at some point.

11 minutes ago, Addicks Fan 1981 said:

heralded a climate change hiatus until July 2013 came round. 

Well, more a string of cool, wet summers than anything which has happened in the past with much cooler results than what was experienced between 2007-2012. The wetness and mildness of that bracket would've been intensified by climate change. Importantly the May-July monsoon of 2007 came after the warmest CET 12 month period on record, so it's likely Atlantic SSTs were absolutely through the roof by this point.

[richie3846]

 TwisterGirl81 I seem to remember this area reached something like 340 hours in May 2020. Isn't the record something like 390 for the UK? 

[B87]

 CryoraptorA303 Assuming we start the summer with a 200 hour deficit, even a repeat of summer 2022 (June 242 hrs, July 250 hrs, August 263 hrs), would need us to see a 230 hour September (which would be the sunniest on record - 2018 saw 210 hours). 

 

[CryoraptorA303]

East Malling achieved 314 hours in May 2020, exceptionally high. Manston got even higher with 331.

Incredibly, Preston is listed as reaching 378! I can somewhat believe this due to the sheltered coastal location from easterlies, but even then it sounds absolutely ridiculous. The next highest is Bournemouth with 353, which sounds far closer to the realms of reality.

8 minutes ago, B87 said:

We are due a 300 hour June or August

Could be this year, you never know. Probably much more likely to be August but no one could be sure of what's ahead.

[TwisterGirl81]

 richie3846 383.9 hours in Eastbourne July 1911 certainly need a couple of those this year, all would be forgiven, boost everyone’s morale….is 400 even possible?

Edited April 24 by TwisterGirl81

[TwisterGirl81]

 Addicks Fan 1981  I checked met office anomaly and sunshine amounts looked just shy of average for here in summer but very wet pretty much everywhere in summer 2007

[B87]

Heathrow sun 1959 vs 2024

Jan: 76 vs 77

Feb: 55 vs 53

Mar: 104 vs 103

Apr: 139 vs 115-125?

May: 221 vs ?

Jun: 232 vs ?

Jul: 277 vs ?

Aug: 240 vs ?

Sep: 209 vs ?

Oct: 150 vs ?

Nov: 53 vs ?

Dec: 30 vs ?

It is theoretically possible, just very very very unlikely.

[CryoraptorA303]

5 minutes ago, TwisterGirl81 said:

is 400 even possible?

Assuming in June and July around 18 hours of sunlight can be received per day, then the physical limit for these months is 527 and 558 respectively. May will be slightly lower than this and August slightly lower than that, etc.. Of course no one expects to ever reach this high but 400 is theoretically well within the realms of possibility for June and July, and at a greater stretch, May and August.

[Addicks Fan 1981]

 TwisterGirl81 summer of 2007 was very busy for insurance companies because people got flooded out of their houses, many were irked as their houses were literally damaged, mind you it was also you could say a good season to canoe on the street sort of thing.