With the record from 1986, the highest March trmp. here in Wembury was 19..5°C on 29th in 2012.
However, not far away at Plymouth Mt Batten it reached 20.1°C.

Len
Wembury

18.9C in Penzance on that date. Since then the highest 17.7C on 25/3/17

MetO are going for 15C for Penzance on Tuesday, however that goes with a forecast 5mph onshore SE wind. Assuming the north coast sea breeze develops, which seems likely, that often backs the wind in Penzance to an NE offshore by mid afternoon. (The NW facing north coast sea breeze is stronger in the afternoon). If that happens then it'll make quite a difference, 19C currently forecast for Bude.

Graham
Penzance

Graham Easterling wrote:

On Sunday, 28 March 2021 at 11:50:29 UTC+1, Nick Gardner wrote:

The last time I reached +20C here was in 2012 with 21.6C on the 29th.

It's never reached 20C in the last 30 years in Penzance. Plenty of high
teens. 20C is unusual here in April.

So far this March has been drier, slightly warmer and rather cloudier
than normal.

1st - 27th
Mean minimum = 3.6C
Mean maximum = 12.5C
Mean = 8.1C
Rain = 37.6 mm (58%)
Sunshine = 104.4 hours


For comparison in Penzance
1st - 27th
Mean minimum = 5.6C
Mean maximum = 11.6C
Mean = 8.6C (+0.0C) (set to change!)
Rain = 49.9 mm (59%)
Sunshine (over the moors at nearby Bosullow) = 108 hours (The average
sunshine over the last 10 years at Bosullow is 118.5 hours) Sunshine at
Camborne = 104 hours Average pressure @ 09:00 = 1024mb

Set to be a bit sunnier than normal, dry & rather warm (assuming the forecast
for the next 3 days is OK!).

It's been a decent month down here, driest March since 2012 & already
marginally warmer than last year. Last time temperature failed to reach 10C
was 13th (9.4C)

Graham
Penzance

In Tideswell the only year with a max over 20C in March in the past 30 years
was in 2012, when it reached 22.4C. The 1991-2020 average highest daily max in
March is 15.4C. At the other end of the spectrum, in 1996, the highest max in
March was only 8.6C.

--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
https://peakdistrictweather.org
Twitter: @TideswellWeathr

Bob Martin wrote:

When did England last get to the end of March without reaching 20 degrees?

It managed to reach this target yesterday, if my newspaper's maximum for
"London" of 21C 69F is to be believed. And it's been even warmer today.
--
John Hall "Hard work often pays off after time, but laziness always
pays off now." Anon

On Tuesday, March 30, 2021 at 3:08:49 PM UTC+1, John Hall wrote:
Bob Martin wrote:

When did England last get to the end of March without reaching 20 degrees?
It managed to reach this target yesterday, if my newspaper's maximum for
"London" of 21C 69F is to be believed. And it's been even warmer today.
--
John Hall "Hard work often pays off after time, but laziness always
pays off now." Anon

Max of 20.5°C here today.
3 deg.C higher than forecast.

Wemnbury , SW Devon

On Saturday, 27 March 2021 at 18:00:03 UTC, Julian Mayes wrote:
Bob Martin wrote:

When did England last get to the end of March without reaching 20 degrees?
My childhood memories (i.e. pre-recent warming) are that this milestone was reached somewhere in the UK (OK, it probably usually was England) around the middle of April. We should not expect 20C in March - and UK temps have been well up to long term averages this month. The record March temperature of 25.6C is going to be approached very closely in the next few days.

Julian
Molesey, Surrey.
Maximum here was 23.7, easily a record (starting 1983), following a min of 3.5. Not quite a record diurnal range but fairly close.
When I was in the Met Office at Bracknell the Office weather station recorded a min of 0°C and a max of 24°C on 29 March 1965. In parts of the country on that day subsided air reached the surface with some very low dew-points.