Low last night of 15C so not the tropical warmth I was expecting.

Currently 20C with medium to high thundery looking cloud but mainly sunny and calm. 

Yes I noticed some showers still moving across the west country. Looking out of my bedroom window to the west I can see the top of some big  clouds in the distance, although it is perfect blue sky here.

Current temp via Blackbushe airport is 21.5C.

Edit: Mark (HW) - check weatherobs.com

Got bad feeing it going wrong today and still have some clouds here so now not excited with it anymore.  That the BIG problem is the cloud now really here to attack any heat records once again.

Watched the sunset as the sun came out very clear before it set while clouds above refusing to clear but see clear skies over Wales that why they got highest temps in Hawarden, that area was very clear and sunny.

Slow start - warmest I can see at 8am is 23C. But the sky does at least have that heatwave look to it - the slightly off-white high ac and the slightly turquoise blue sky.

I have a feeling today will be a slow burning ever-so-slight disappointment, while tomorrow will be more of the classic "what, it's only 7am and already 55C" kind of day. Though I note the models have slightly reduced overnight temps now. Only showing 25C in London on GFS whereas previously it was 26 and occasionally 27.

You know it's going to be a hot one when you pop out to empty some buckets of water on the garden (from a water butt) and when you get back indoors it's already gone up 1.5 degrees!

Simply phenomenal rates of increase here, it's just about to break 25. (My neighbouring stations already have).

25. (Yes, that was 0.3C since my last post).

Next stop - 30... at this rate it'll be less than 2 hours.

Warmest 0700Z (8am) reading on the mainland seems to be 24.5C in Sheffield. Both Jersey and Guernsey are over 25C.

No, just spotted Okehampton is at 24.6C. IIRC that weather station is at a remote farm high up on Dartmoor. Clearly height is best at the moment!

It's a real shame we've lost Gravesend - and that Brogdale isn't an automatic station.

If either of the above were in play you'd be seeing 27 or 28 by now. (Going by the many PWS which are showing 28+ in north Kent right now.)

Where can you see the Sheffield temp (and others that aren't on Weatheronline or Ogimet)?

It's on the map at Weatherobs.com. It has a synop code (99107) so I assume it is an official Met station (it was quoted in the 2019 heatwave article on the Met Office site too).

The WOW site shows quite a few but some are clearly a bit dodgy. (Is the one in Leysdown yours by any chance?)

That is fantastic, also has Ryhill and Bramham which I will be keeping an eye on. 

Has Doncaster airport but that might not be an official one, just an airport?  If so, it is concern that there isn't a weather station on the flat plains/Vale of York all the way from South of Doncaster up the Vale of York as tomorrow that could see the record high. 

Yup, that Leysdown one is mine. It's a daytime fan-aspirated Davis VP2, so should be reasonably accurate (the fan is certainly whirring away like mad now!)

FWIW, way more people use Weather Underground:

https://www.wunderground.com/wundermap?lat=51.397564&lon=0.900857&zoom=13&tl.play=0&tl.spd=2&groupSevere=1&groupHurricane=1&groupFire=1&groupCamsPhotos=1&groupRealEstate=1&eyedropper=0&extremes=0&fault=0&favs=0&femaflood=0&fire=0&firewfas=0&fissures=0&fronts=0&hurrevac=0&hur=0&labels=0&lightning=0&livesurge=0&mm=0&ndfd=0&rad=1&rad.num=1&rad.spd=25&rad.opa=81&rad.type=00Q&rad.type2=&rad.smo=1&rad.noc=1&rad.stm=0&dir=1&dir.mode=driving&sst=0&sat=0&seismicrisk=0&svr=0&ski=0&snowfall=0&stateLines=0&stormreports=0&tor=0&tfk=0&tsunami=0&riv=0&wxsn=0&cams=0&pix=0

Up to 26.4C now.