Diurnal range

[Spurry]

-3.3 last night and it hit 16.0c today here in Sunny Wigan , so thats a 19.3 range

[Osbourne One-Nil]

Argh - go on oil ya lawn mower.

Is that a euphemism?

I drove back through Swaledale earlier this evening and whilst my (pretty accurate) car thermometer was reading 11C (at about 5pm), there was still a very heavy frost in the valley bottom, which is a pretty massive difference over a few hundred yards. I guess there was no breeze to mix the air. Plenty of snow pockets in the hills too still.

[Bobby]

The range here seems to be about 13c lately. -1 by night and around 12c by day. Today reached 13c though so if it can get to -1 it'll be even a bigger range.

[Stratos Ferric]

Just poking around the interweb and found this from 2005

Source: www.metoffice.gov.uk/UK climate trends

It looks like the average diurnal temp difference for February from 1900 onwards is 18.2 DgC but I can't find reference to the record highest range... yet

Coast, can you clarify that please. It reads to me as if you're saying Feb averages a range of 18.2C but there absolutely no chance that that's correct. Without checking I'd reckon that typically it would be comfortably sub 10.

[Osbourne One-Nil]

Does that mean the difference between the coldest recorded UK temp and the highest? No....that wouldn't be diurnal. I'll shut up now.

[Stratos Ferric]

Does that mean the difference between the coldest recorded UK temp and the highest? No....that wouldn't be diurnal. I'll shut up now.

Not that that ever stopped hares running here on N-W. It's slightly off topic but my favourite in recent times - notwithstanding the current fashion for "inversions", which are this year's "polar low", which in turn was last year's "cold air advection" - was the GFS plot someone posted pre-Christmas showing how the -25C air in the middle of the Alps had apparently made a migration from Norway (bear in mind this is a 100 km2 parcel of air) and was now headed towards the UK.

I think that you're probably somewhere close to the money Os. Maybe we should have a competition: the answer is 18.2C in February. What is the question?

Does that mean the difference between the coldest recorded UK temp and the highest? No....that wouldn't be diurnal. I'll shut up now.

By the way, I'm sure I'm not alone in saying that it's wonderful when you start getting all meteorologicial.

[Osbourne One-Nil]

Ah well....I saw some clouds today. Right funny looking ones they were. Like upside down Noddy hats.

[Stratos Ferric]

Ah well....I saw some clouds today. Right funny looking ones they were. Like upside down Noddy hats.

They'll have been cumulo-noddyats then. Usually a sign of a large diurnal range.

[acbrixton]

Coast, can you clarify that please. It reads to me as if you're saying Feb averages a range of 18.2C but there absolutely no chance that that's correct. Without checking I'd reckon that typically it would be comfortably sub 10.

Reminds me of the time, when working part time as an NHS domestic (winner of the coveted title of best lavatory cleaner in successive years) some 25 years ago, a colleague dismissed, disdainfully, data showing a fall in the annual rate of inflation with the assertion that "well prices in Budgens still keep going up" (but then again she also stated that "if I had a gun I would shoot that Thatcher, I would" before opining that I was fortunate to live in the small town of Byfleet, Surrey as "there aren't many foreigners" [she meant non-whites although Italians were regarded as honorary non-whites]. I thought this rather weird (to say the very least) at the time although I now see a semblence of coherence: an admirably succint account of BNP policy...

regards

ACB

[chionomaniac]

Does anyone know what the minimum diurnal range has been in this country? I know that there has been days when the temperature has seemed to stay the same but has this actually happened in practice or to within 0.5ºc say?

What weather would be more likely to have a smaller range?

c

[johnholmes]

a cloudy one with a slack sw drift I would think, early and late not winter or summer, just a guess?

Edited February 15, 2008 by johnholmes

[reef]

a cloudy one with a slack sw drift I would thin, early and late not winter or summer, just a guess?

Id say this current pattern is the one for low diurnal ranges, cloud keeping temperatures down by day and up by night. Its definitely one of Bottesford's favourites (or not, hehe) Today has been a fine example here, a min' of 5.1C and max' of 5.9C. So a range of just 0.8C.

Edited February 15, 2008 by reef

[stewfox]

Does anyone know what the minimum diurnal range has been in this country? I know that there has been days when the temperature has seemed to stay the same but has this actually happened in practice or to within 0.5ºc say?

What weather would be more likely to have a smaller range?

c

Did anyone find the record diurnal range for the UK, if there is one recorded ?

Must be something above 20c in a day ? I thought May would be a good contender ?

No stats I guess re the least change

Of course many days when the temps drop from night time but the least change ? London often had max 10c min 8c type of stuff

Edited February 15, 2008 by stewfox

[Coast]

Coast, can you clarify that please. It reads to me as if you're saying Feb averages a range of 18.2C but there absolutely no chance that that's correct. Without checking I'd reckon that typically it would be comfortably sub 10.

Sorry SF, only just got back to this one!

The info came from T A Harley's site on British Weather, in particular the page on February

Reading back through it I will admit it is not stating that the min and max were for the same day (or even the same year) and are therefore not valid data for a single day diurnal range - hands up, mea culpa!!!

I just can't find anywhere on the web anything that gives the biggest CET diurnal range on a single day, so I give up, someone else can go find it :lol:

Now about those Noddy hat clouds.......

Edited February 15, 2008 by Coast

[reef]

Did anyone find the record diurnal range for the UK, if there is one recorded ?

Must be something above 20c in a day ? I thought May would be a good contender ?

No stats I guess re the least change

Of course many days when the temps drop from night time but the least change ? London often had max 10c min 8c type of stuff

I think its 30th December 1995 in Altnaharra. The temperature rose from a min of -27.2C early in the morning to 1.5C in the afternoon, so a range of 28.7C. More impressively though, the midday temperature was -21.2C, but around -1.0C less than 3 hours later.

[Weather-history]

Did anyone find the record diurnal range for the UK, if there is one recorded ?

Must be something above 20c in a day ? I thought May would be a good contender ?

The one often quoted is Tummel Bridge on the 9th of May 1978

Min: -7C

Max: 22C

A diurnal range of 29C

[reef]

The one often quoted is Tummel Bridge on the 9th of May 1978

Min: -7C

Max: 22C

A diurnal range of 29C

I wondered about that one, but wasnt sure as the temperature records on this site say it was only -2C then?

http://www.tutiempo.net/en/Climate/TUMMEL_...-1978/30600.htm

I cant find any nearby sites with records for that date and the synoptics look a bit mild for -7C. But Still, it could be possible.

[Stargazer]

I wondered about that one, but wasnt sure as the temperature records on this site say it was only -2C then?

http://www.tutiempo.net/en/Climate/TUMMEL_...-1978/30600.htm

I cant find any nearby sites with records for that date and the synoptics look a bit mild for -7C. But Still, it could be possible.

I wouldn't be surprised if Rickmansworth featured there somewhere too with its famous artificial frost hollow and notably warm days...0 to 30 anyone?

[Edit]

Found a reference to Rickmansworth on the BBC web site: http://www.bbc.co.uk/weather/features/unde...hollows.shtml...

"Large temperature ranges can also be recorded in frost hollows. Rickmansworth, a very well know frost hollow, recorded the largest daily temperature range in England when, on 29th August 1936, the temperature climbed from 1.1°C at dawn to 24.9°C within 9 hours!"

Looks like Tummel Bridge still has it.

Edited February 15, 2008 by Stargazer

[Norrance]

Tummel Bridge had the record from -7C to + 22C but was just beaten by Altnaharra at the end of December 1995 by point something. Interestingly Tummel Bridge was in May, Altnaharra in December and I believe that the previous record in Central Southern England was in August showing that the largest diurnal ranges are not limited to any one particular season.

Edited February 15, 2008 by Norrance

[Red Raven]

Big changes in diurnal range - just look at my graph!

I might beat you tonight with lowest temp - I notice my station recorded the second lowest temp in the COL 07 report (unless i missed someone)

Edited February 15, 2008 by Red Raven

[chionomaniac]

a cloudy one with a slack sw drift I would think, early and late not winter or summer, just a guess?

Thats what I originally thought would be the best (worst) weather for keeping the temperature constant for a period of time. I also wondered would daytime freezing fog be another situation when the temperature not fluctuate much but wasn't so sure.

c

[Stratos Ferric]

Tummel Bridge had the record from -7C to + 22C but was just beaten by Altnaharra at the end of December 1995 by point something. Interestingly Tummel Bridge was in May, Altnaharra in December and I believe that the previous record in Central Southern England was in August showing that the largest diurnal ranges are not limited to any one particular season.

In theory they could occur at any time, though the odds favour spring and autumn because the potential for both warm days and cold nights is at its highest: if anything, I'd favour spring; in autumn the sea is at its warmest and would modify anything but the stillest of flows. The current Hadley norms actually show a different reality - with the winter range appearing to be the largest, however I'd offer a slight caution on this. Given that we warmed across the last period of measurement, and moreso in winter than summer, the higher ranges shown MIGHT simply reflect that at the start of the period minima were lower than by the 90's, and at the end maxima were warmer than in the 60's. Inferring mean range from the difference between long period mean max and mean minimum is potentially flawed.

The two stations you cited are frost hollows. I suspect the central S England station is Rickmansworth. If so, it's worth noting that "Ricky" is also a notorious frost hollow, occasionally returning air frost even in summer, and not infrequently returning a ground frost even in August. It's quite possible that the combination of soil (if sandy) and location could combine to present an anomalous situation in which conditions favour a larger summer range, however, as a rule this would be unusual. Spring tends to be favoured because the sea and land temperatures are lagging the air, and are still cold enough to allow overnight temperatures to fall low fairly readily in the right conditions; coupled to this the sun is climbing and the air, by day, can be warmed considerably.

Edited February 16, 2008 by Stratos Ferric

[Terminal Moraine]

The huge diurnal range in December 1995 at Altnaharra was due to a change in air mass as a persistent low level inversion with intense cooling over a period of several days was replaced by a air mass of Atlantic origin.

The rise in temperature once the inversion was broken down was spectacular, from a reading of -21.2c at 1200 on Dec' 30th to -1.0c by 1500. The temperature continued to rise slowly for the rest of the 30th and by 0900 the next morning, the end of the official meteorological day, it had reached a max' of 2.1c; the previous night's minimum was -27.2c.

This also contributed to the greatest annual range in temperature within the British Isles, 62.4c, as the year's max' was 35.2c at Boxworth, Cambridgeshire on August 1st.

[Stu_London]

In theory they could occur at any time, though the odds favour spring and autumn because the potential for both warm days and cold nights is at its highest: if anything, I'd favour spring

I would also cite the tendency for days with very low humidity in March / April to also be a factor in making spring the most diurnal of the seasons

[TonyH]

From -7.7c to +9.3c here today, thats......17.0c, so another decent range.