Friday 12 January 2024

Weather log December 2023

Weather log December 2023

Key:


WW = West Wales
Lwn = Llanwnnen
AG = Aldermans Green, Coventry
CL = Church Lawford
LL = Long Lawford
ROW = Ross-on-Wye, Herefordshire
CC = Capel Curig, Snowdonia
MH = Milford Haven
Carms = Carmarthenshire
Pembs = Pembrokeshire
Mids = Midlands
CITE = Coton-in-the-Elms, Derbyshire
COL = Climatological Observers Link
PWS = Personal weather station
MO = Met Office
NRW = National Resources Wales
EA = Environment Agency
est = estimated
inc = including
cf= compared with

A cold start to Winter 2023/24:

Fri 1st hard but beautiful hoar frost, Llanwnnen min -7.8c appears amongst the coldest in the UK (Shap -9c). Other lows Pershore -6.6c, Whitechurch -6.0c, CITE -5.8c, Tirabad/ Sennybridge -5.7c, Trawsgoed -5.0c, Coleshill -4.9c, Mona -4.3c, Pembrey Sands -2.8c, Nottingham -1.9c, Aberdaron & Mumbles 0.0c. Many places a cold or very cold day and for Wales & MW Mids generally sunny, maxima Pennerley, Salop -0.7c, CL 0.9c, Lwn & Nottingham 1.1c, CC 1.8c, Coventry 2.7c, Aberporth 3.4c, Pershore 3.7c, Astwood Bank 3.8c, Trawsgoed 5.7c, Gogerddan 6.2c, Valley 7.9c.

Sat 2nd severe frost for much of Wales and the Marches; here at Llanwnnen -10.1c was the coldest reading this early in the Season since -11c on November 30th 2016; other minima Tirabad -9.0c, Shobdon -8.7c, Shawbury -8.5c, Hereford -8.2c, CC -7.2c, Nottingham & Pembrey Sands -5.9c, Trawsgoed -5.5c, Coventry -3.5c, CL -3.3c, Aberporth -2.9c, Aberdaron +0.8c. Cold for many by day, fog slow to clear parts of the Midlands where widely an ice day (sub zero maxima): daytime maxima (to 1800 0r 2100): Shobdon -2.1c, CL & Nottingham -1.5c, Pershore -1.1c, CC +1.6c, Lwn & Trawsgoed 4.4c, MH 7.6c. 

Sun 3rd snow affected N and W Mids late evening and overnight with appreciable falls for Staffs & Derbyshire in particular (widely 2 to 4 inches, > 6 inches Peaks), 1 or 2 cm lay across Birmingham & Coventry first thing, while it did not settle a little to the SE (Rugby & Warwick snow-free). Temperatures rose above freezing overnight for the Midlands, while for much of WW it was less cold with some rain, sleet or snow. Coventry had only reached -1.4c to Sunday evening, rising to 1.7c by dawn with the snow starting to melt by then.

Mon 4th an inch of rain in places 24 hours to 0900 (Coventry 23mm, Lwn 12mm); somewhat less cold most areas, further rain for N & W Mids in particular, along with an almost continuous shower streamer down the Irish Sea across Pembrokeshire, wettest 24 hours to 2100, Scolton Country Park (Pembs) 33.2mm, Nottingham 25.8mm, ROW 27.2mm. Rather cold maxima mainly 5 to 7c (Pershore 8c, MH 7.5c, Coventry 6.1c, Lwn 5.1c, Nottingham & Shawbury 4.2c, CC 3.9c).

Tue 5th Scolton Park max 9.4c warmest in UK, other MH 8.4c, CL & Lwn 5.7c, CC 5.1c.

After a drier couple of days, return of mild air, rain and wind:

Thu 7th wet day, over an inch parts of SW Wales; rather mild WW, mildest for a fortnight. Porthmadog 12.8c mildest in UK, also Lwn 9.9c, ROW 9.3c; Whitechurch, Pembs 32.0mm officially wettest in Wales, however Maenclochog (also Pembs) 43mm (midnight to midnight).

A pair of Met Eireann named storms did not impact Wales so much over the weekend:

Sat 9th named storm (by the Irish Met Office) Elin rather insignificant here, brought 81mph gusts to Capel Curig (not unusual for this windy location).

Sun 10th named storm Fergus (again Irish named) rather non event here produced some sferics near Machynlleth afternoon.

Wed 13th Scolton Country Park (Pembs) max 10.7c warmest in UK.


First half of December variable in terms of rainfall, ranging from about average parts of mid & NW Wales to over twice the average along the south coast of SW Wales and parts of the Midlands. After the cold start temperatures are now running close to average/ rather mild. Sunshine- wise dull to average (best parts of WW).

Rainfall totals December 1st to 0900 16th: 

Llanwnnen 72.8mm (average)

Coventry 73.2mm (very wet)

King's Newnham, Warks (EA) 59.8mm (very wet)


A drier interlude around mid month and when mild/ very mild:

Sat 16th Hereford 14.1c (warmest in UK), Trawsgoed 12.7c, CITE 12.1c, Coventry 11.3c, Lwn 10.3c, CC 9.4c.

Mon 18th wet day, widely an inch WW, locally 2 inches.

Tue 19th Lwn 22.6mm 24 hours to 0900. Gogerddan (near Aberystwyth) 32.8mm, wettest MO site in UK (24 hours to 2100, Lwn 17mm same period).

A very mild and at times wet run up to Christmas, maxima 10 - 12c, minima close to 10c:

Sat 23rd/ Sun 24th wet at times, Wales in particular widely an inch or more mid & N: Trawsgoed 25.6mm (to 0600) and Lwn 22.3mm (0900) while Corris (NRW), near Machynlleth 57.2mm (midnight) wettest UK gauge.

Christmas Eve (Sun 24th) one of the mildest minima widely above 10c (MH 10.8c, Shobdon 10.4c). 12 to 14c by day light rain or drizzle. Coventry mildest Christmas Eve on rec max 13.8c (beating 13.3c 1997). Other maxima Pershore 14.5c, CL & Nottingham 13.5c, Trawsgoed 12.7c, Lwn 11.9c, Aberdaron 11.7c. Again much rain for mid & N Wales in particular, Corris NRW 51.6mm making over 4 inches in 48 hours with quite bad flooding of the river Dyfi.

Christmas Day (Mon 25th) very mild night again, minima Mumbles & Pembrey Sands 11.2c, MH, Pershore & Trawsgoed 10.9c, Lwn 9.8c, Nottingham 8.8c, CC 8.6c. A mild/ very mild Christmas Day too generally highs 10 - 12c; maxima ROW 12.6c, Pershore 12.4c, Pembrey Sands & Shobdon 11.6c, Coleshill & Coventry 11.5c, Nottingham 10.6c,  Lwn 10.2c, CC 9.8c. Cloudy with spells of rain for many.

Overall the Christmas period was dull and mild with rain at times.

Wed 27th named storm Gerrit brought heavy rain and strong winds with damage in places. Gusts to 85mph at Capel Curig (Snowdonia) and widely WW above 50mph. Widely 1 or 2 inches rain for Wales, showery by evening with hail and thunder in places. A brief but spectacular thunderstorm here at Lwn 10pm, 3 brilliant flashes under a mile west of here with loud, crashing thunder along with a 5 minutes rain and hailstorm. Another very mild day, maxima Trawsgoed 13.2c, CC 13.1c, Pembrey Sands & Pershore 12.8c, Lwn 12.2c (mildest day of the month), Aberdaron, CL, Hereford & Nottingham 11.9c. Coventry 11.6c. Libanus (Powys) 49.8mm wettest in Wales, Shobdon 25mm wettest in Mids, also Nottingham 22.4mm.

Thu 28th showers or longer spells of rain, again local hail and thunder.

Sat 30th 1 or 2 inches widely WW and close to an inch parts of Mids (where fell late in day/ overnight), Scolton Country Park (Pembs) 33.8mm officially wettest in the UK to midnight. 0900 readings: Lwn 30mm, Abergorllech (Carms) 46mm Rhos Ymryson 37mm (both NRW), CL 20.4mm.

New Years Eve (Sun 31st) showery, a dry day parts of Mids. Flooding across Warwickshire inc Coombe Park, Brandon and Caludon fields (all Coventry area).



Nature notes:

Tue 5th Aberaeron, plenty of flowering plants still on the coast, meaning no severe frost yet (doubt its yet been below -3c cf -10c inland) inc Roses, Red Valerian, Buttercups and Daisies. 8 Curlew flew over between Aberaeron & Aberarth, have seen good numbers (close on 100) on adjacent fields a few years back.

Mid month first Bluebell spikes.

Sat 23rd 2 Blackbird in song, one in town dusk, the other by Morrison car park early evening.

Boxing Day (Tue 26th) Mistle Thrush singing weakly garden.

Fri 29th Neuadd lane much fresh growth especially Celandine and ferns; Song Thrush singing well dusk. 

Year end: much fresh growth again with most of December very mild, Bluebell spikes now well up and Celandine foliage well advanced. Garden hedges have swollen buds on some shrubs. Plenty of Bluebell spikes inc a few at LL (Warks). Note photo of a Daffodil in bloom from Hereford (since Boxing Day). Daff spikes at the usual early spot in the village.


December 2023 summary

Very mild and wet/very wet, dull.

Double the average rain in places.

Less than half average sun some places.

Most places 2 to 3c above average.


Rainfall totals December 2023

Capel Curig, Snowdonia 444.2mm (128%)

Mona, Anglesey c 150mm (wet)

Trawsgoed, Ceredigion c 240mm (very wet)

Llanwnnen 225.1mm = 120% of 2006 - 23 station average (187mm) but 156% of the historical local December average (144mm)

Pembrey Sands, Carms 237.8mm (190%)

Milford Haven, Pembs 226.2mm (183%)

Mumbles, near Swansea 205.8mm (180%)


Nottingham c 165mm (over twice average)

Shawbury, Salop c 100mm (very wet)

Coleshill c 135mm (twice the average)

Coventry, Bablake School 144.0mm (232%)

CL, Warks 122.3mm (215%)

Pershore, Worc 121.2mm (206%)

Shobdon, Herefordshire 147.8mm (171%)


National Resources Wales (NRW) rain gauges Dec 2023

Llyn Cefni, Ynys Mon 177.4mm (very wet)

Bethesda Quarry (Gwynedd) 272mm (wet)

Cwm Dyli (Snowdonia) 493.2mm (very wet)

Corris (near Machynlleth) 516.6mm (very wet)

Bow Street (near Aberystwyth) 207.4mm (almost twice average)

Pontrhydfendigaid (near Tregaron, Ceredigion) 225.2mm (very wet)

Penuwch (Ceredigion) 390.3mm (highly dubious as surrounding stations below 250mm)

Rhos Ymryson (near Gorscoch and 5 miles NW of Lwn) 234.8mm (very wet)

Cellan (2 miles NE of Lampeter) 219.6mm (very wet)

Pencader (Carms)  256mm (wet)

Abergorllech (Brechfa Forest, Carms) 266.6mm (very wet)

Rhydargaeau (Carms) 281.8mm (very wet)

Garnswllt (near Ammanford, Carms) 255.8mm (very wet)

Felinfoel (near Llanelli, Carms) 212.4mm (very wet)

Ferwig (near Cardigan) 153.6mm (rather wet)

Maenclochog (near Preselis, Pembs) 366.2mm (almost 200%)

Tenby (Pembs) 256.6mm (over 200%)

Bolton Hill (near Haverfordwest, Pembs) 246.4mm (very wet)


COL stations rainfall Dec 2023

Llansadwrn 172.8mm (127%)


Ludlow, Salop 137.1mm (165%)

Alvechurch, Worc 174.3mm (211%)

Warstock, Brum 147.6mm (191%)

Cosby, Leic 98.2mm (156%)

Hinckley 135.1mm (201%)

Towcester, Northants 115.5mm (167%)


Sunshine totals Dec 2023

Llanwnnen estimated  26 hours (69%)

Coventry, Bablake School 32.4 hours (53%)

Shobdon, Herefordshire 21.2 hrs (38%)


COL stations sun Dec 2023

Ludlow 29.2 hrs (50%)

Alvechurch 31.9 hrs (54%)

Cosby 31.9 hrs (47%)

Towcester 34.9 hrs


2023 annual summary

Very mild and wet/ very wet; sunshine rather dull to average

Here at Llanwnnen the mildest year recorded with a mean temperature 12.6c (just pipping 2011 12.5c), while rainfall of 1642mm made it the second wettest year (1737mm 2020). Past 5 years have  averaged 1506mm against 2006-23 average 1404mm, and the even lower historical Lampeter average of 1312mm. Most rain days (248 days over 0.2mm and wet days (204 days over 1mm) since recording began. No snow lay at all in 2023.

Coventry had one of the wettest years on record, 903.8mm the wettest since 1966 (928mm); only 2022 a milder year in the city.


Rainfall 2023

Coventry 903.8mm (131%)

Church Lawford 774.5mm (115%)

Llanwnnen 1642.0mm (117% of 2006-23 here and 125% of the historical Lampeter average)


NRW gauges rainfall 2023

Bethesda Quarry 1834mm

Cwm Dyli (Snowdonia) 3817mm

Corris (near Machynlleth) 2947mm

Bow Street (near Aberystwyth) 1191mm

Rhos Ymryson (5 miles NW of Llanwnnen) 1753mm

Cellan (2 miles NE of Lampeter) 1485mm

Rhydargaeau (near Carmarthen) 2048mm

Felinfoel (near Llanelli) 1659mm

Tenby 1485mm


Sunshine 2023

Coventry 1589 hours (102%)

Llanwnnen (est) 1200 hours (89%)






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