Weather log May 2021
Sat 1st frosty start to May in many areas, minima St Harmon, Powys -5.4c, Pembrey Sands -3.1c, Shobdon -2.3c, Lwn -1.4c, CL +0.1c, Nottingham 3.5c, Mumbles 4.2c.
Mon 3rd first significant rain fell in most places for over a month, widely an inch or more for Wales with much of the Midlands having over half inch...also a very cool and windy day..gusts to 74mph at Mumbles Head and even 48mph Llanwnnen well inland; max below 10c in places such as Nottingham 9.1c and Coventry 9.3c.
24 hours rain totals to 0600 Tue 4th:
Capel Curig 65.4mm, Trawsgoed 30.4mm, Llanwnnen 25.3mm (0900), Winterbourne 20.4mm, Nottingham 20.0mm, CL 15.2mm, Coleshill 13.0mm, Mumbles 6.6mm
Tue 4th very cool and showery, hail in many places and thunder for a few...
First week often very cool with further frosts in places...showers wintry in places, snow settling for some high ground of Wales..most places having at least one day max below 10c.
Sat 8th wet day as milder humid SW winds arrived after a long absence, some hilly parts of S Wales received over 6 inches as judged from the radar, with a National Resources Wales rain gauge at Croeserw north of Maesteg recording over 100mm (Derek Brockway); other totals to midnight Tirabad 54.0mm, Pembrey Sands 53.8mm, Shobdon 30mm, Llanwnnen 26.0mm, Coventry 23.0mm, Aberporth 17mm, Coleshill & Pershore 16mm.
Sun 9th briefly warm for much of the Midlands in the warm sector associated with the yesterday's rain, maxima Pershore College 20.9c, Nottingham 19.7c, Coventry 19.6c, Shobdon 15.8c, Mona & Trawsgoed 15.4c, Llanwnnen 13.9c, Aberdaron 12.8c.
Showers and some longer spells of rain through the mid month period, these thundery with heavy hail locally:
Fri 14th (19.2mm) and Sat 15th (25.8mm) at Swyddffynnon in Ceredigion (just north of Tregaron Bog) was the wettest spot in the UK due to catching plenty of downpours. A PWS near Talsarn just 7 miles north of Llanwnnen recorded 49mm Sat 15th
A very wet first half to May most places having already exceeded the whole May average with some spots nearing twice the average:
Llanwnnen, Ceredigion May 2021 rainfall to date:
Mid month total (to 0900 16th May) 120.5mm.
This is 157% of the whole May average (77mm).
Wettest May historically hereabouts is 1967 when the closest rain station 1 mile away measured 194mm while another 3 miles away had 228mm and so these would be the next totals under threat!
Other rainfall totals 0900 16th:
Coventry 82.4mm
CL 51.6mm
Mean temperatures are running 2 or 3c below the May average (1981-2010) as of mid month!
Wed 19th a dry bright reprieve after all the recent showers, some places attained average May temperatures and it was one of the milder days this month so far..max Pershore 18.3c, Coventry 16.6c, Lwn 15.2c, Pembrey 15.1c, Shawbury 14.6c, Aberporth 12.5c (cool NW sea breeze here on the exposed coast).
Thu 20th - Fri 21st a deep Spring low crossed the country bringing strong winds and heavy rain (particularly to W Wales). Winds gusted widely to over 50mph across Wales and up to 73mph at Pembrey Sands. This was one of the windiest May days here as we do not usually get gusts over 40mph by late Spring. Prolonged rain for Wales over the two days giving widely above 2 inches with over 4 inches for some higher ground...all this rain meant the May record has already been smashed at Llanwnnen (over 180mm for the month by afternoon 21st this some 30mm over May 2006 the previous wettest). Also two very cool days, especially so 21st with no locations above 13c and quite a few Welsh ones not topping 10c! Max 9.5c at Lwn the second coolest May day (8.2c 14/05/13) and the coolest day this far into Spring; other maxima Tirabad 8.7c, Aberdaron 9.6c, Trawsgoed 9.8c, Coleshill 11.2c, Market Bosworth 11.3c, Valley 12.1c, Pershore 12.4c
48 hour rainfall totals to 0600 22nd: Capel Curig 111.2mm, Trawsgoed 62.4mm, Llanwnnen 59mm, Nottingham 18.8mm, CL 16.4mm, Mumbles 11.2mm, Shobdon 10.8mm.
Sat 22nd May 2021 rainfall Llanwnnen so far:194.8mm (254% of the whole May average).
It has now become the wettest May in over a century hereabouts from what I can find (British Rainfall and other records).
May 1967 had 194mm a mile from here and 228mm 3 miles away (that may also be topped with so many days remaining), however...
Much drier and warmer towards month end:
Sun 30th warm and sunny feels like Summer! Maxima Lwn 24.1c, Porthmadog c 24c, Trawsgoed 22.3c, ROW 20.7c, Shawbury 20.0c, CL & Hereford 19.3c, Aberporth 19.1c.
Mon 31st another warm and mostly sunny day, max Lwn 23.3c, Sutton Bonington (Notts) 22.9c, Pershore & Trawsgoed 22.7c, CL & Coventry 22.0c, Shobdon 20.9c, MH 18.7c.
Nature notes
Sun 2nd first Swift seen briefly from garden mid afternoon.
Wed 5th single Swift again here.
Thu 6th foresty first Cuckoo calling quite a bit, at one stage called almost non stop for almost 10 minutes at about 200m or so.
Fri 7th 4 Swift above the gardens teatime.
Early May and trees reluctant to leaf, few Oaks properly out yet with most Oak and Ash barely beginning to leaf; Sycamores are though well out and Horse Chestnut.
Tue 11th 4 Swift screaming Lampeter; 8 - 10 Swift here.
Wed 12th 2 Cuckoo forestry, many Willow Warbler (WW) and Chiff Chaff (CC), 2 Newts, Muntjac glimpsed.
Leaf burst now happening mid month as we have had much milder nights..
Bluebells peaking mid month.. the garden ones now going over with many having been flattened or gone soggy with all the rain. Last Daffs (those in the container by the garden wall) mid month are very late as rarely are they blooming into May..
Sun 16th GSW drumming heard from Neuadd Lane in the village (this is late).
Mon 17th forestry laughing Yaffle (Green Woodpecker), Redstart, one Cuckoo heard
Wed 19th Tregaron Bog nice sunny if rather cool afternoon, 2 Hobby (I think) as seemed too small and slim for Peregrines? Cuckoo heard but only faintly as distant; plenty of warblers (CC, WW, Blackap, possible Garden Warblers).
Most Oaks and Ash getting into leaf month end...Oaks are very late Ash less so..
Month end countryside Bluebells still going strong in shade; first Laburnums Maestir
Sun 30th Forestry I or 2 Cuckoos calling after sunset to 2200; no Nightjars surprisingly as it was a rather warm still evening; Fox; 3 Newts bottom track near main road that is often flooded.
May blossom out month end.
Very poor Apple blossom this year, it attempted to bloom mid month but too much rain and wind, so very little.
May 2021 summary
Very cool and very wet; generally dull
Record breaking May rainfall in places with Wales especially wet, locally 3 times the average and where the wettest May srb 1862. Coolest May generally since 1996.
Rainfall May 2021
Mona 124.4mm
Aberporth 144.0mm (266%)
Llanwnnen 215.6mm (280%)
Milford Haven 112.2mm
Pembrey Sands 131.4mm (189%)
Mumbles 120.0mm (191%)
Shawbury 117.0mm (218%)
Coleshill 105.8mm (200%)
Coventry, Bablake School 123.6mm (221%)
Church Lawford 99.2mm (176%)
Pershore 115.6mm (218%)
Shobdon 125.4mm (227%)
COL/ PWS rainfall
Llansadwrn, Anglesey 140.3mm (207%)
Cosby, Leicestershire 91.0mm (158%)
Warstock, Bham 121.2mm (188%)
Daventry, Northants 84.3mm
Towcester, Northants 116.1mm (193%)
Alvechurch, Worcestershire 131.1mm (198%)
Ludlow, Shropshire 118.1mm (185%)
Sunshine May 2021
Valley 209.2 hours
Aberdaron 211 hrs
Aberporth 145.5 hrs (70%)
Llanwnnen (estimated) 131 hrs (72%)
Shawbury 139.4 hrs (85%)
Coventry 154.1 hrs (79%)
Shobdon 154.3 hrs
Spring 2021 summary
Cool and generally rather wet
March near average; April very dry, very cool and sunny; May very wet and cool.
Rainfall totals Spring 2021
Aberporth 192.8mm
Llanwnnen 290.6mm (122%)
Milford Haven c 176mm
Mumbles c 166mm
Shawbury 154.6mm
Coleshill c 142mm
Coventry 177.2mm (114%)
Church Lawford 157.6mm (104%)
Sunshine Spring 2021
Aberdaron 610.7 hours
Aberporth 495.6 hrs
Llanwnnen (estimated) 447 hrs (105%)
Shawbury 451.2 hrs
Coventry 473 hrs (98%)
Shobdon, Herefordshire 478.2 hrs
