Are those official stations? If so then fair enough. Must have been a quite localised bubble of heat over Wales!

Maxed out at 10.5C here, foggy all day!

Yeah they are official - as docmog says, with a south-easterly wind, being to the north-west of the Cambrian mountains allows a foehn effect to take place, or blocking of the air near the surface which has been cooled, allowing warmer air aloft to descend close to the surface. Sunny weather over there would have helped too.

It reached 19.1 at Tredegar today at 360 metres.

For what its worth, the 1400 ob shows a drop in temperature as the wind turns westerly - can't see an obvious synoptic reason for that to happen so maybe a sign of a weak sea breeze pushing inland?

http://www.weathercast.co.uk/world-weather/weather-stations/obsid/3503.html

Local factors such as the length of sunshine in a specific spot, and the topographical effects upon a certain air mass via adiabatic warming combined with wind direction can do these things over very short distances.  The GFS 0z +12 hours map I posted this morning had a blob of the warmest colours right over Trawsgoed, so it was always expected to be in the firing line.  There is no need to cast doubt on this record (the second monthly record so far of a remarkable year) at all.

Fohn effect helped smash the record today. Fully legitimate. 

November 1946 had similar temperatures in North Wales and we know what happened after that!

Can confirm from Machynlleth where it didn't reach the dizzy heights of Traws but went well over 21C for a while in the early afternoon. It was like a summer's day here. Huge diurnal range too I imagine - heavy dew and fog here early and late. A memorable UK weather day.

Indian summers (an Americanism, of course) only occur after the first "killing frost". As it's been remarkably frost-free for most so far, then no, it's not an Indian summer - just a warm spell.

If we can get the wind direction a little more into the SW then we could see some truly staggering temperatures, we are not taking full advantage of foehn because the wind is in the wrong direction. Consider the previous 21.7C record was done in uppers of only 8C, that's a good 4C lower. Potentially 25C is possible with these uppers and a SWerly wind. Trouble is getting both is nigh impossible. 

Foehn seems to have setup in Scotland. Could see the scottish record fall today, most likely location is Aviemore. 

Highest temperature at 1200 is 19.9 at Swyddffynnon (19.4 at 1200 yesterday). Trawscoed lagging behind on 19.5 at the moment (18.9 at 1200 yesterday). Just 6.7 at Llysdinam in the fog in the Upper Wye valley over the other side of the Cambrian mountains.

Question: is it Trawscoed or Trawsgoed?

I had been wondering that too. I know that on streetmap it is Trawscoed (Crosswood) on one level of magnification (1:50,000) but Crosswood/Trawsgoed on another level of magnification (1:100,000) 

Gogerddan (just inland from Aberystwyth) warmest at 1300 with 20.7C

11.1c   @   13:30.  Due to Fog.

Trawsgoed is the modern name of the House/Estate and therefore the name used by the Met Office.  

However, Trawscoed is the correct Welsh spelling ...

i assumed it was an English vs Welsh spelling issue, like Porthmadog/Portmadoc. 

Anyway, 22.3C the max today (well yesterday now) so only 0.1C lower than Nov 1!

While it is quite unlikely that high temperatures records will be toppled from here onwards, it does look like the unusually mild theme with some places still getting to touch the 60 F mark is set to continue for at least a good week or so.
 
I know the coldies amongst us will throw their arms up in despair over that, but my lawn is loving it, that's for sure.

18C at the moment in the Midlands, truly insane first week Of November. Tuesday looks potentially record breaking once again.

23.6c    @    08:30

22.6c    @    12:00

22.3c    @     1458.  Humidity inside 72%rh......

A warm, muggy feeling this afternoon in some brighter spells, 16c the high.