While the absolute maximun of 20.3C in Trawscoed was impressive in that it broke the February and winter all time record and earliest 20C record one other thing I'm wondering is the dirunal variation record.

The variation in Trawscoed stands at 20.6C given a minimun of -0.3C was recorded this morning. I wonder how close this is to the record? The only situation, I can think of, where a higher extreme might be reached would be an extreme nightime low of, say, -25C followed by a warm front and then something like a 10C high. But has that ever happened?

 

So my question is. What is the dirunal variation record? What is the record for February? Also out of curiousity what is the lowest variation recorded? 0.0C?

 

Also one final point to chew over. At several points today the warmest place (usually Trawscoed) was less than 100km away from the coldest place (also in Wales).

 

 

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Record is 29.3C on 30 December 1995, I believe (a big rise from the joint record low of -27.2C to just above freezing, at Altnaharra).

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Apparently on 30 Dec 1995 it was -21C at midday at Altnaharra! Then the temperature rapidly rose by 20 degrees in less than three hours in the afternoon.

No idea about other records, but the second biggest diurnal range I can find was 28.3C, from 1.1C to 29.4C, on 29 August 1936 at Rickmansworth.

 

Edit: actually there as a 29.0C range from -7.0C to 22.0C on 9 May 1978 at Tummel Bridge. https://www.trevorharley.com/weather_web_pages/1978_weather.htm

 

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Think mid July 2006 had some impressive ranges, but not as high as those. The nights were unusually cool considering there was a significant heatwave afoot.

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We had a 20C diurnal range on one day in July 2013, from 9C to 29C, which is quite impressive for summer. In March 2012 we had a couple of days that went from below freezing to above 20C.

20C diurnal ranges aren’t that uncommon in spring.

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No idea about other records, but the second biggest diurnal range I can find was 28.3C, from 1.1C to 29.4C, on 29 August 1936 at Rickmansworth.

 

 

 

 

The data for that day when Rickmansworth recorded that large diurnal range.

GMT Temp F
1am 38.8
2am 37.9
3am 36.2
4am 35.1
5am 34.4
6am 35.5
7am 46.7
8am 58.3
9am 70.7
10am 74.1
11am 78.0
12pm 80.9
1pm 83.0
2pm 84.5
3pm 84.5
4pm 83.1
5pm 79.7
6pm 69.2
7pm 56.8
8pm 51.1
9pm 47.7
10pm 46.6
11pm 45.7
12am 44.1

The lowest reading for the thermometers in the standard screen were 34.0F and the highest reading was 84.9F

The radiation thermometers ranged from 26.3F to 150.4F

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A good range here today....-1.4c at 6.30am.....17.1c at 15.20pm....range of 18.5c over 9hrs....pretty impressive without a change of airmass....

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Bala in Wales went from -2.3c to 20.0c today

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I was impressed with my diurnal range today.

0.8c at 7am to 18.4c at 3pm. 

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0.7 to 16.8 here, impressive indeed for this locale in February.

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Pershore had a low of -3C at 6 am and a high of 18C at 4pm,so an impressive range of 21 C. We haven't broken the all time midlands Feb temp record yet,which currently stands at 18.7 C.But a good chance that could fall on Tuesday,many places in the midlands forecast 16-17 C so a few spots could be in the running for 18C+

Interestingly the three largest diurnal ranges noted above came at very different times of year. Altnaharra in the depth of Winter, Tummel Bridge in Spring and Rickmansworth in high Summer.
I lived about ten miles from Tummel Bridge in 1978 and my mother kept weather records for Radio Scotland weather watchers. She noted a min of -5C that day up to a max of 21C.

 

 Also out of curiousity what is the lowest variation recorded? 0.0C?

 

On a technicality, I found this on uk.sci.weather: https://groups.google.com/forum/#!topic/uk.sci.weather/q0GtFIIPnOc

 

Last night I was updating my daily weather statistics for this month 
and I came across what I thought must be an error. The stats showed 
that the maximum and minimum temperature for the 14th were both 8.7°. 
On checking, I found that this was, in fact, correct and was due to the 
somewhat unusual behaviour of the temperature during the period 
13th-15th. On 13th Oct the max was 19.5° at 1440z. From then, there was 
a gradual temperature fall right through into the morning of the 14th 
reaching 8.7° at 0900z on the 14th. This was the lowest temperature in 
the 24 hours to 0900z on the 14th and therefore counts as the min for 
the 14th. After 0900z on the 14th, the temperature continued to fall 
gradually throughout daytime on the 14th then became steady on about 7° 
during the night of 14th/15th. By 0900z on the 15th it had risen to 
only 7.4°. The max temp for the 14th is the highest temp between 0900z 
on the 14th and 0900z on the 15th which was 8.7° at 0900z on the 14th. 
It is therefore correct that the min and max for the 14th were both 
8.7°. I can't recall recording a similar occurrence previously. 

 

 

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Pershore had a low of -3C at 6 am and a high of 18C at 4pm,so an impressive range of 21 C. We haven't broken the all time midlands Feb temp record yet,which currently stands at 18.7 C.But a good chance that could fall on Tuesday,many places in the midlands forecast 16-17 C so a few spots could be in the running for 18C+

 

Yep,the all time feb max temp record for the midlands fell on Tuesday.Pershore reached 19C,which actually wasn't the highest in the midlands.4 weather stations recorded 19C ,with the new record now set at 19.1 C. Now sure what the diurnal range was though,was a slight frost so must have been close to a range of 20C again

interesting topic, and to ad into the mix... what is the quickest temperature rise of the same?

ie - from google:
Spearfish holds the world record for the fastest recorded temperature change. On January 22, 1943, at about 7:30 a.m. MST, the temperature in Spearfish was −4°F (−20°C). The Chinook wind picked up speed rapidly, and two minutes later (7:32 a.m.) the temperature was +45 °F (+7 °C) above zero.

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