Yesterday saw a drop in temperature. A maximum of 11.8C, under patchy cloud spreading out from inland This compares with 13.9C max on 14th, and follows 2 days of virtually unbroken sunshine.

Combined with an increase in wind from a generally F2 to F4, yesterday felt a fair bit cooler.

Then -0.2C last night, the 1st air frost since 9th March.

Notably late for Penzance. It is the 2nd latest air frost in my 30 year record, after 21/4/95. Only the 8th air frost I've ever recorded in April.

Graham
Penzance

Notably late for Penzance. It is the 2nd latest air frost in my 30
year record, after 21/4/95. Only the 8th air frost I've ever recorded
in April.

Amazing Graham, weve had 10 air frosts & 14 ground frosts so far in
just 16 days!!

Mean is still only 4.2c the same as February 2021. It must warm up soon.

Graham (Weston Coyney)

On Friday, 16 April 2021 at 12:58:03 UTC+1, Graham wrote:

Notably late for Penzance. It is the 2nd latest air frost in my 30
year record, after 21/4/95. Only the 8th air frost I've ever recorded
in April.

Amazing Graham, weve had 10 air frosts & 14 ground frosts so far in
just 16 days!!

Mean is still only 4.2c the same as February 2021. It must warm up soon.

Graham (Weston Coyney)

The Lands End peninsula is almost an island, so there needs to be just a gentle breeze in just the right direction to allow an air frost at this time of year.

Having said that we've had a lot of near misses. 9th - 1.1C, 12th 0.9C, 13th 0.4C, 14th 1.4C.

It's also currently the coldest April in my 30 year record, by a significant marging. Mean 7.6C, previous coldest 8.6C in 2013. Though 3 years have had lower mean maximums.
So far:-
Mean Max:- 11.9C (-1.8)
Mean Min:- 3.4C (-3.4)

Cold, very dry & very sunny here. Approx 120 hours of sun over the moors at Bosullow (4 miles to the NW) up to 15th. It must be around 140 hours right on the coast. The advantage of being at the end of a long peninsula (especially in spring) away from land based convectional cloud, in a situation like this.

Graham
Penzance

On 16/04/2021 12:58, Graham wrote:
Amazing Graham, weve had 10 air frosts & 14 ground frosts so far in
just 16 days!!

Mean is still only 4.2c the same as February 2021. It must warm up soon.

I've never known an April like this before. So far I have recorded 12
air frosts and 13 grass frosts. Admittedly they have all been slight
with the temperature just dipping down below freezing before dawn.

Normally frosts disappear in April, all gone by mid-April at the latest.
The persistent coldness of this month has been remarkable, I was asked
at work today if it was ever going to warm up. I suggested that it might
next week. April 2013 was cold but not as chilly as this month so far
but what a glorious summer then followed, so there's hope!

April 1st - 16th
Mean min = 0.5C (-4.6C)
Mean max = 13.3C (-1.8C)
Mean = 6.9C (-3.2C)
Rain = 1.2 mm
Sunshine = 114 hours.

Calm, clear, starry nights have dominated leading to all those frosts.

Soils bone dry, dust blowing around in any wind.

--
Nick Gardner
Otter Valley, Devon
20 m amsl
http://www.ottervalleyweather.me.uk

On Friday, April 16, 2021 at 7:35:15 PM UTC+1, Nick Gardner wrote:
On 16/04/2021 12:58, Graham wrote:
Amazing Graham, weve had 10 air frosts & 14 ground frosts so far in
just 16 days!!

Mean is still only 4.2c the same as February 2021. It must warm up soon.
I've never known an April like this before. So far I have recorded 12
air frosts and 13 grass frosts. Admittedly they have all been slight
with the temperature just dipping down below freezing before dawn.

Normally frosts disappear in April, all gone by mid-April at the latest.
The persistent coldness of this month has been remarkable, I was asked
at work today if it was ever going to warm up. I suggested that it might
next week. April 2013 was cold but not as chilly as this month so far
but what a glorious summer then followed, so there's hope!

April 1st - 16th
Mean min = 0.5C (-4.6C)
Mean max = 13.3C (-1.8C)
Mean = 6.9C (-3.2C)
Rain = 1.2 mm
Sunshine = 114 hours.

Calm, clear, starry nights have dominated leading to all those frosts.

Soils bone dry, dust blowing around in any wind.

--
Nick Gardner
Otter Valley, Devon
20 m amsl
http://www.ottervalleyweather.me.uk
These negative temperatures remind me of 1986; the coldest April for decades. After the 20th. it started to warm up. ? This year, too!
Wet though; so not a precedent being set for this year in the light the poor Summer which followed in 1986.
That April was one of several months across 1985-1986 which were exceptionally cold.
Warm, dry Aprils (2007,2011, 2015) were followed by cool summers. I agree, perhaps this year will echo 2013, though rainfall was about average here (45.9mm) So far this time, we are still under 1mm.

Peter Lea-Cox, Umborne