The averaging period used for the following assessment was 1981-2010.
At the start of May, the UK was in an unsettled westerly regime, but after a frontal system had brought rain south-eastwards on the 1st and 2nd it soon turned much warmer and, for most places, sunnier, giving the warmest early-May Bank Holiday since the holiday was introduced in 1978. The second week was cooler but still with a fair amount of dry sunny weather for many parts. The second half was generally warm with high pressure dominating and easterly winds bringing further warm sunshine, but it was often cooler and cloudier near the east coast. During the last week showers, thunderstorms and longer spells of rain broke out increasingly widely, especially in central and southern areas.
The provisional UK mean temperature was 12.1 °C, which is 1.7 °C above the 1981-2010 long-term average, making it provisionally the equal second warmest May in a series from 1910. Mean maximum temperatures were between 2 and 3 °C above average in most areas, while mean minimum temperatures were mostly about 1 °C above average. The mean maximum temperature for the UK as a whole was the highest in a series from 1910. Rainfall was 69% of average, and most places had a dry month but rainfall was generally close to normal across central and southern England. Sunshine was 132% of average, and with the exceptions of south and west Cornwall and more locally in north Wales and northern Scotland, sunshine was above average almost nationwide, especially so in northern England, and it was provisionally the sunniest May in a series from 1929.
The UK monthly extremes were as follows: A maximum temperature of 28.7 °C was recorded at Northolt (Greater London) on the 7th. A minimum temperature of -4.6 °C was recorded at Aboyne (Aberdeenshire) on the 1st. In the 24 hours ending at 0900 GMT on the 28th, 81.0 mm of rain fell at Winterbourne (West Midlands). Wind gusts of 59 knots (68 mph) were recorded at South Uist (Western Isles) on the 11th.
On the 1st, Southeastern Rail services were disrupted between Maidstone and St Pancras due to heavy rainfall. There were ferry cancellations and delays; also some roads were closed in Norfolk. Further rain on the 2nd led to a landslip in Port Talbot’s Afan Valley, which closed Cymmer Road, with one or two minor roads closed in the area due to flooding. During the next week impacts from thick fog were reported with a few ferry services suspended.
During the third week of May, quiet dry sunny weather led to increased risk of wildfires and there were reports of a gorse fire near Craig’s Forest in Finvoy, near Ballymoney, Northern Ireland.
Heavy showers and thunderstorms caused some impacts during the last week of May. At the start of the week some roads became flooded around Birmingham, and one lane on the M25 was closed due to flooding at junction 6. On the 26th, flooding occurred on the M5 southbound near Halesowen with the whole motorway shut between junctions 2 and 3. On the 27th, the Birmingham Street Iftar was cancelled, a man died after his car became submerged in floodwater in Walsall, and part of the M5 was closed. Three buildings were struck by lightning in Leamington and Kenilworth, and over 1000 homes were left without power across the Midlands. Water Rescue Boats were deployed in Northampton to help residents affected by flooding. In Wales, there was widespread flooding with some roads being blocked and cars and homes left under water in Welshpool. In the east of England, lightning caused major disruption to refuelling at Stansted Airport. From the 29th onwards, flooding around London caused delays to transport services: some A-roads were affected, and Southeastern Rail reported disruption to some trains due to lightning having damaged signalling equipment. Some flights at both Gatwick and Stansted were delayed due to adverse weather. In Kent some roads were blocked due to floodwater, the M2 between junctions 6 and 5 being closed for a time; meanwhile in Southampton some roads were flooded.
England diary of highlights
May began cool and unsettled with westerly winds, but it soon turned generally sunny and warm or even hot, and the hottest day of the spell coincided with the early May bank holiday. The period 10th-17th was generally cooler, but the second half was mostly warm and sunny away from eastern coasts, with mostly easterly winds. Thundery showers affected many areas during the last week.
The mean temperature for May was provisionally 1.7°C above the 1981-2010 long-term average, making it the equal warmest May (alongside 1992 and 2008) in a series from 1910. Rainfall was 79% of average and it was generally drier than average in the north, the south-west, and the east of East Anglia but the Midlands and south-east mostly had near-average rainfall. Sunshine was 136% of average, making it the second sunniest May (after 1989) in a series from 1929.
1st to 4th
The 1st started sunny, but frosty in places with a minimum of -4.2°C at Redesdale (Northumberland), then rain spread into northern and western parts after midday, clearing eastwards on the 2nd followed by sunshine and scattered showers, these wintry on high ground. Needles (Isle of Wight) recorded gusts to 55 mph on the 2nd. A ridge of high pressure brought a dry sunny start in most places on the 3rd but it clouded over from the west with patchy rain and drizzle into northern and western parts, and most parts stayed cloudy on the 4th but it was sunnier in the south-east and brightened up in the north later in the afternoon.
5th to 9th
This was a generally settled, sunny and increasingly warm period although western and south-western coasts were often affected by mist and fog with cool onshore winds. The 5th-7th had plenty of sunshine for most, with temperatures widely into the low 20s Celsius on the 5th, the mid 20s Celsius on the 6th, and Northolt (London) recorded a high of 28.7 °C on the 7th, the month’s highest. The 8th remained sunny and warm in the east but western areas were cloudier and much cooler with rain crossing the north. The 9th was bright or sunny in the east, but rain spread from the west after midday.
10th to 17th
It was cooler during this period but still with a fair amount of dry sunny weather. Early rain over East Anglia and the south-east on the 10th cleared eastwards, then it was generally sunny with a few isolated light showers. It clouded over from the west on the 11th with rain spreading into western parts, and the frontal system was slow to clear eastern areas on the 12th and 13th, with rain mainly for the south-east which spread as far north as the North York Moors on the evening of the 12th. Elsewhere it was generally dry and sunny. The 14th and 15th were generally sunny and warm away from coasts but rain reached the far north by the evening of the 15th. The rain belt spread slowly south during the 16th, followed by brighter but cooler weather with a maximum of only 9.0 °C at Fylingdales (North Yorkshire). Following a frosty start in some northern parts, the 17th was a sunny day but cool near eastern coasts.
18th to 24th
High pressure and easterly winds brought mostly warm and sunny weather except near the east coast. The 18th-20th were generally sunny, but mist and low cloud persisted near some south- and east-facing coasts, especially in south-eastern counties, and cloud and light rain spread into the far north on the 20th. Showers, locally heavy in the Midlands and south, broke out on the 21st, otherwise it was mostly sunny after clearance of early patchy fog in places. The 22nd and 23rd saw more widespread cloud near eastern coasts and some showers for the south-east but continued sunny and warm elsewhere. Cloud, showers and longer spells of rain developed more widely in the Midlands and south on the 24th and it remained grey and misty near the north-east coast, but Morecambe (Lancashire) recorded 15.5 hours of sunshine on the 23rd and 24th.
25th to 31st
Thundery showers became more widespread during this period. A belt of rain, heavy at times, spread north-westwards on the 25th. The 26th was mostly sunny after a cloudy showery start for some, but showers and thunderstorms developed in the south-west by evening. The night of the 26th/27th was notably warm for some with a minimum of 16.3 °C at Otterbourne (Hampshire), and on the 27th thunderstorms affected many parts of the Midlands and south with 81.0 mm of rain at Winterborne (West Midlands) in a very short space of time, but there was plenty of warm sunshine elsewhere. The 28th was very warm in places with sunny spells after low cloud burned back to the east coast, but a few showers broke out, mainly in the south-east where they were locally thundery. The month ended with three somewhat cloudier days. There were persistent thunderstorms around London on the 29th, and rain and showers, locally heavy and thundery, spread north-westwards on both the 30th and 31st although the 31st remained generally dry in the north.
Wales diary of highlights
May started off cool and unsettled with westerly winds, but the rest of the month saw plenty of warm sunny weather, with easterly winds common in the second half. The last week, while still warm, was rather unsettled with rain or showers and some thunder at times.
The mean temperature for May was provisionally 1.2 °C above the 1981-2010 average. It was a generally dry sunny month with 75% of average rainfall and 125% of average sunshine, but rainfall was close to normal in many eastern parts of the country.
1st to 4th
It was generally cool and unsettled. After a sunny start on the 1st, with a frost in places, it turned wet and windy from the west, with a maximum of just 9.8 °C and winds gusting to 56 mph at Capel Curig (Gwynedd), and Whitechurch (Dyfed) saw 33.2 mm of rain. The rain turned showery from late morning on the 2nd and the afternoon was mainly dry and sunny. The 3rd started bright, but cloud increased with locally heavy rain crossing the north early in the afternoon, and the 4th was another mostly cloudy and cool day although it brightened up in the north during the afternoon.
5th to 10th
With relatively high pressure and southerly winds, the 5th to 7th were sunny and increasingly warm for much of the country but it was much cooler near coasts, especially west-facing, with persistent low cloud for some. The 8th started sunny for most but rain, mainly in the north, crossed the country from late morning. The 9th started bright before rain spread to all parts by early afternoon, but this had cleared by the 10th, which was a day of sunshine and isolated showers.
11th to 15th
Rain spread from the west to most parts on the 11th, but this cleared away, followed by three mainly sunny days from the 12th to 14th, and Valley (Anglesey) recorded 14.6 hours of sunshine on the 13th. With clear skies and light winds the night of the 13th/14th was cold in places with Sennybridge (Powys) falling to -2.4 °C early on the 14th. Misty and cool around the coasts on the 15th, sunny and warm inland but it clouded over later ahead of rain arriving during the evening.
16th to 23rd
Rain cleared southwards on the 16th followed by cooler weather and a frost in a few places early on the 17th. High pressure brought dry sunny weather from the 17th to 19th and it turned warmer again. Most places remained sunny on the 20th but Anglesey and the west coast were cloudier with a little light rain in the afternoon. Warm sunny weather resumed between the 21st and 23rd, although some low cloud affected the east early on the 23rd, this burning off quickly leaving sunshine.
24th to 31st
This period continued warm but more unsettled. The 24th and 25th were generally cloudy and wet but it dried up by evening on the 25th. The 26th was a day of sunshine and showers, with thunderstorms for some southern parts in the evening, and bands of showers and thunderstorms were widespread on the 27th, but it was very warm with a maximum of 26.8 °C at Hawarden (Clywd). Low cloud on the 28th burned off by afternoon, then it was sunny with a few showers in the south-west and across Snowdonia. The following night was warm with a minimum of 15.8 °C at Aberdaron (Gwynedd), and the 29th was sunny down the west coast, with 15.1 hours of sunshine at Valley (Anglesey), but cloudier elsewhere with showers across the south from late afternoon. The 30th and 31st were generally cloudy with rain or showers which turned heavy and thundery by late afternoon on the 31st.
Scotland diary of highlights
May began cool and changeable with westerly winds, and it remained quite changeable for the first half of the month but from the 5th onwards it was often warm, with a fair amount of sunshine at times especially in eastern areas. The second half of the month was more settled with high pressure dominating and plenty of warm sunshine, although it was often cooler and cloudier near the east coast.
The mean temperature for May was provisionally 1.9 °C above the long-term average, making it the equal warmest May (alongside 2008) in a series from 1910. Rainfall was below average except in the Western Isles, with 55% of average overall. Sunshine was above average except in parts of the far north, and with 129% of average overall, it was Scotland’s sunniest May in a series from 1929.
1st to 4th
The 1st started sunny and frosty with Aboyne (Aberdeenshire) falling to -4.6 °C overnight, but rain soon spread from the west with 23.0 mm at Threave (Kirkcudbrightshire). The rain cleared eastwards on the 2nd followed by sunshine and showers, the showers wintry on high ground, and the temperature only reached 8.0 °C at Lerwick (Shetland). The 3rd was dry and bright in the east but cloud and rain/drizzle spread from the west, and the 4th was mostly cloudy and cool but brighter in the north-east.
5th to 9th
It became warmer as the winds turned southerly, but remained quite changeable. The 5th was sunny and warm in the north and east but cloudier and cooler with patchy drizzle in the south and west, and the 6th was a mostly sunny and warm day but with cloud and intermittent rain in the far north. Rain was more widespread over the north on the 7th but it was still warm with hazy sunshine in the south. The 8th and 9th both had rain bands spread eastwards during the day followed by sunshine and showers.
10th to 15th
The 10th was a day of sunshine and scattered showers. The 11th was dry but cloudy and windy, a belt of rain spreading from the west and winds gusting to 68 mph at South Uist (Western Isles). The rain cleared the north-east by noon on the 12th, leaving mostly sunny weather with a few afternoon showers for the south. The rain returned and affected many areas early on the 13th before clearing northwards to allow some sunshine. The 14th and 15th were sunny and warm in the east but cloudier in the west, and patchy light rain spread from the west late on the 15th.
16th to 21st
The 16th was sunny everywhere but much cooler with a few showers in the far north, and this led to a frost in some places early on the 17th, which was another sunny day. The north and west were cloudier on the 18th with some light rain, but it remained dry with some sunshine elsewhere, and the cloudier skies were more confined to the far north-west on the 19th with most places dry and sunny. The 20th and 21st both saw more widespread cloud and rain, but the 21st was sunny in the east.
22nd to 31st
Rain over the north-east cleared early in the day on the 22nd but it was cloudy and cool except in parts of the south and the Western Isles. The 23rd to 25th were generally cool and cloudy along the east coast but sunny and warm elsewhere, although late on the 25th cloud and rain spread into southern parts. The 26th to 28th were sunny almost everywhere, with low cloud near the east coast tending to burn away quickly, although the 26th had a few showers in central areas. Kirkwall (Orkney) and Kinloss (Morayshire) recorded 15.9 hours of bright sunshine on the 27th, and the temperature did not fall below 15.8 °C at South Uist (Western Isles) on the night of the 27th/28th. The 29th was warm and sunny for most with a high of 27.5 °C at Achnagart (Ross & Cromarty) but low cloud spread from the east, especially in the south-east. The 30th had some light rain in the south during the evening and the 31st had a few showers in the north and west; otherwise it was generally warm and sunny but low cloud continued to affect the east coast on both days.
Northern Ireland diary of highlights
May started off cool and unsettled but from the 5th onwards it was generally warm. The first half remained generally unsettled but there was a lot of dry sunny weather in the second half of the month when high pressure was often close by and easterly winds were frequent.
The mean temperature was provisionally 1.6 °C above the long-term average. It was a generally dry sunny month overall with 80% of average rainfall and 123% of average sunshine, but some western parts had close to average rainfall.
1st to 4th
After a cold night with a minimum of -2.0 °C at Katesbridge (County Down), the 1st was dull and wet with a maximum of only 7.9 °C at Killylane (County Antrim). The 2nd was a breezy day with sunshine and scattered showers. The 3rd was a generally wet day but the rain turned lighter and patchier during the afternoon, and the 4th was also mostly cloudy but brightened up during the afternoon when it also turned warmer.
5th to 10th
It became warmer during this period but the weather remained changeable. The 5th was a mostly cloudy day, but some sunshine broke through in the afternoon, and the 6th was generally sunny and warm. Cloudy weather returned on the 7th with some patchy light rain, and the 8th and 9th both had rain early in the day clearing from the west followed by sunshine and showers. The 10th had a mix of sunshine and scattered showers.
11th to 15th
On the 11th a spell of wet and windy weather spread eastwards with gusts to 55 mph at Banagher (County Londonderry), clearing to sunshine and showers by evening. The 12th and 13th were mostly sunny with well-scattered light showers, but the 14th was cloudier with a little rain. After a bright start on the 15th, cloud increased with a band of rain spreading south-eastwards during the afternoon.
16th to 22nd
With high pressure now dominating, the 16th and 17th were dry and sunny following cool starts and there was a frost in a few places early on the 17th. The 18th was cloudier with some patchy light rain, but still with some sunny spells, and the 19th was mostly sunny, but turned cloudier towards evening. Slow-moving fronts then brought generally cloudy wet weather from the 20th to 22nd, with 28.8 mm recorded at Banagher on the 20th.
23rd to 31st
Easterly winds brought generally warm weather and plenty of sunshine but also some showery outbreaks. The 23rd was a warm and sunny day after low cloud quickly burned off, and the 24th was also mostly warm and sunny but cloud and a few showers developed from late afternoon. The cloud and light showers cleared early on the 25th leaving another sunny day. The 26th-28th were mostly warm and sunny, but there were a few well-scattered showers on the 26th and more widespread showers on the 27th, and the night of the 27th/28th was notably warm with a minimum of 15.4 °C at Killowen (County Down). The 29th was another warm sunny day with a maximum of 25.3 °C at Castlederg (County Tyrone), and Aldergrove (County Antrim) recorded 15.4 hours of bright sunshine. The 30th was also warm and sunny, but the 31st started with showers and longer spells of rain, which cleared away into the afternoon leaving some sunshine.