The mean April minimum for Rostherne up to the 17th is a remarkable -0.5C

---

Day 18...managed to scrape another one! Cloudier today but there's a chance that we could get some breaks again later tonight.

Aboyne WMO

06GMT min / grass min
01 Apr -0.5 -3
02 Apr -4.4 -10
03 Apr -1.6 -7
04 Apr -3.3 -7
05 Apr -4.0 -5
06 Apr -2.3 -4
07 Apr -1.3 -3
08 Apr -2.1 -7
09 Apr -1.0 -3
10 Apr -6.2 -12
11 Apr -6.1 -12
12 Apr -4.9 -10
13 Apr -5.5 -12
14 Apr -6.0 -11
15 Apr -6.3 -11
16 Apr -7.3 -11
17 Apr -3.4 -7
18 Apr -1.2 -5

---

Another -4C here last night.

---

Another -4C here last night.

Are you in a frost pocket like Redhill valley? 

I dont think we got much below freezing last night,  only ice on the car windscreen, not the bird bath

---

Very cold yet again across the south this morning. Not that unusual to get -4C in mid April but generally that only happens once or twice at most in any given year. This year is quite unusual for the number of air frosts.

Farnborough -4.1C

Benson -5.1C

Benson has recorded 10 air frosts this month with six being below -4C

Bournemouth airport has recorded 11 air frosts all of which have been -2C or lower. This includes one stretch of 6 days unbroken and another of 5 days. Another night just missed out with a minimum of 0.1C.

 Frostiest April i can ever remember here, not so hard this morning , still down to -2 though. Grass is being burnt off day by day.

Day 18...managed to scrape another one! Cloudier today but there's a chance that we could get some breaks again later tonight.

Aboyne WMO

06GMT min / grass min
01 Apr -0.5 -3
02 Apr -4.4 -10
03 Apr -1.6 -7
04 Apr -3.3 -7
05 Apr -4.0 -5
06 Apr -2.3 -4
07 Apr -1.3 -3
08 Apr -2.1 -7
09 Apr -1.0 -3
10 Apr -6.2 -12
11 Apr -6.1 -12
12 Apr -4.9 -10
13 Apr -5.5 -12
14 Apr -6.0 -11
15 Apr -6.3 -11
16 Apr -7.3 -11
17 Apr -3.4 -7
18 Apr -1.2 -5

That's incredible.

---

13 air frosts here this month including 11 in succession which was the longest since December 2010.

Previous highest number of frosts I recorded in April was 9 in 2013. Highest total at nearby Craibstone in the past 70 years was 11 in both 1966 and 1968.

Since my records began in May 2005 these are the only month to record as many as 13 air frosts:

December 2010 - 19

December 2009 - 17

March 2013 - 16

January 2009 - 14

January 2021 - 14

February 2010 - 13

February 2016 - 13

 

Just shows how utterly pathetic winter has become when so many months cannot even muster half the frosts an April can. Winter 2016/17  only had 12 air frosts in total so this April has recorded more than that entire supposed winter season 

Air frost duration has been 74.5 hours which is nearly double my previous record of 38.9 hours in 2013. It's more than the last two dire Decembers could manage combined and in fact more than every single December has managed since 2013 except for 2017. Ludicrous.

Todays minimum of 3.9C was the warmest of the month so far but only just above the long term average min for April. Contrast this with last December, one of the worst ever, which saw 12 consecutive nights fail to even drop below 4C 

---

I’m in East Yorkshire, West of Bridlington near the ‘foot of the Wolds’. This April has been exceptionally bad for the garden. 14 frosts so far at night, 11 below -2 and 4 of these have been between -5 and -6 

So the 18th night was the final one in this remarkable run of consecutive frosts - last night the cloud remained over us and the minimum was 5.8C so the run is well and truly ended.

Inspection of MIDAS and WMO data for Aboyne gives 5 spells of 14 consecutive nights or more with minimum air temperature below zero since 1989:

Start 2001-01-05 End 2001-01-21 17 days
Start 2008-12-23 End 2009-01-06 15 days
Start 2009-12-18 End 2010-01-12 26 days
Start 2010-12-31 End 2011-01-14 15 days
Start 2013-03-19 End 2013-04-04 17 days

Unfortunately the automatic station malfunctioned at the end of November 2010 and did not resume until 31st December so there are no records covering the remarkably cold December 2010. Braemar had 2 spells of 16 and 17 days while Balmoral had spells of 17 days and 30 days during December 2010 / January 2011 so it's possible that Aboyne would have exceeded 18 days in the second spell.

However this spell of 18 days in April 2021 is the second longest at any time of the year based on the existing data, which is pretty incredible.

 

---

There could be some large diurnal temperature ranges by the end of the week. Friday looks potentially quite notable - low single figures, maybe even frost in the morning, then mid-to high teens by afternoon.

---

Very cold run of nights at my field in Kent too. Here’s the run of minima for the month:

1. 4.9
2. 5.2
3. 5.4
4. 4.4
5. -3.4
6. -2.9
7. -3.3
8. 0.8
9. 2.0
10. 3.7
11. -2.2
12. -3.5
13. -3.9
14. -3.3
15. -4.4
16. -3.2
17. -5.1
18. -3.6
19. -1.4

Mean month to date -0.7C

Already down to 4.2C after a max today of nearly 15.

Several days below 40% RH too.

---

Yet another frost this morning -2 down the road.

BBC radio forecastersaid 15 frosts on the ground out of 20 days this month in Scotland. Regrettably imprecise, 'on the ground; not clear if this was at a single station, but you get the general idea.

---

BBC radio forecastersaid 15 frosts on the ground out of 20 days this month in Scotland. Regrettably imprecise, 'on the ground; not clear if this was at a single station, but you get the general idea.

A strange statistic given that Aboyne has had 18 air frosts so far this month.

---

 

A strange statistic given that Aboyne has had 18 air frosts so far this month.

True, and even Edinburgh Gogarbank has had 17 ground frosts during this month so far with 13 of those also being official air frosts.

 

---

According to the Met Office, we have just had our coldest start to April since 2013 with temperature anomalies averaging around -2.3°C across the UK, based on the 1981-2010 April average for the UK as a whole.

Last winter contained some very cold spells which brought us minus double digit temperatures to here in Edinburgh on one occasion for the first time since December 2010, and at least one official ice day to many parts of the UK (though not to here in Edinburgh), yet that was only an average winter here overall in terms of the temperatures with two out of the three winter months actually being milder than average overall.

Based on all of that, it would have been very interesting to see just how cold last winter might have been if we had sustained a similar temperature anomaly during that period to what we have seen during this month until now, and even how much more in the way of snowfalls which we might have got during that winter of 2020/21 if that had been the case.

---

 

Are you in a frost pocket like Redhill valley? 

I dont think we got much below freezing last night,  only ice on the car windscreen, not the bird bath

We are in the Blackwater valley, same as Farnborough which is often one of the coldest spots on still clear nights. The soil is sandy heathland around here and loses heat rapidly, then the cold air drains into the valleys so yes it is often colder here than most places across the south. A touch of frost on the cars and grass again last night but the air temp only dropped to about 2C.

---

Already down to -2 C tonight in Milfield, N Nor'land, 14 air frost of month, more than any month since i started records here in Dec2013.

-1.8C and the 15th air frost here for this month. Eskdalemuir's minimum average this month is -3.2C up to the 20th!

The frostiness of this April has been remarkable.

---

-1.8C and the 15th air frost here for this month. Eskdalemuir's minimum average this month is -3.2C up to the 20th!

The frostiness of this April has been remarkable.

Dipped down to -2.8C

---