The averaging period used for the following assessment was 1981-2010.
UK climate video
The cool theme which characterised spring continued into May, with temperatures somewhat below average for much of the month. Winds were often from a northerly direction, although there were a few warmer days in some areas. It was also unsettled at times, particularly in northern and western areas; the 14th was particularly wet over much of England and Wales. In between the unsettled spells there was some pleasant spring sunshine.
Temperatures for May were below average everywhere. The UK mean temperature was 9.5 °C, which is 0.8 °C below the 1981-2010 average, making it the coldest May since 1996. The month was much wetter than average across parts of north-east England and north-west Scotland, and also rather wet in south-west Scotland, Northern Ireland, the English Midlands and south Wales. The UK overall had 132% of average rainfall. There was 95% of the long-term average sunshine for the UK overall, with some north-western areas being rather dull and the sunniest areas being towards the south-west.
A maximum temperature of 23.8 °C was recorded at Drumburgh (Cumbria) on the 7th. A minimum temperature of -5.5 °C was recorded at Alston (Cumbria) on the 2nd. In the 24 hours ending at 0900 GMT on the 15th, 87.3 mm of rain fell at Llanforda Reservoir (Shropshire). A wind gust of 74 mph was recorded at Needles Old Battery (Isle of Wight) on the 14th and again on the 24th.
There were unseasonably strong winds over a large part of central and southern England and Wales on the 9th, widely gusting at 50 mph.
South-west England and south Wales experienced heavy rain from 14th to 15th, with 40 mm or more falling widely on 14th and some reports of localised flooding in Wales. On the morning of 15th, a few locations in Shropshire and Dartmoor briefly experienced lying snow. Winds gusted at 60-70 mph over exposed extremities of Cornwall and the Isles of Scilly. Several thousand homes in Cornwall were without power overnight and there were reports of fallen trees.
England diary of highlights
May began with a spell of fine weather, but from 8th onwards it became much more unsettled with heavy rain and strong winds at times. Temperatures remained generally below average with some notably cold days. The last week became drier and brighter, but temperatures still struggled to reach seasonal-average values.
The mean temperature was 1.0 °C below the 1981-2010 average, the coldest May since 1996. Rainfall was well above average in the north-east and the Midlands, and England overall had 122% of average. The sunshine total was 99% of the long-term average, slightly brighter in parts of the south-west and dullest in the north-west.
1st to 7th:
The 1st and 2nd were dry and sunny, as high pressure built from the south. It remained dry and sunny again for many on 3rd, although rain reached the far north-west during the evening. The 4th was more unsettled with scattered showers for central and eastern areas. A ridge of high pressure built from the south resulting in fine weather from 5th to 7th; temperatures reached 22 °C in central and eastern areas, but the highest value was 23.8 °C at Drumburgh (Cumbria) on 7th.
8th to 15th:
A change to more unsettled conditions began on 8th, with rain spreading from the west during the afternoon on strengthening westerly winds. The 9th saw further rain spreading from the west, with strong winds for southern areas giving gusts to 58 mph. There were showers for northern areas on 10th, and more general rain reached the south-west during the afternoon; it remained windy with gusts of nearly 50 mph on the south coast. The 11th was showery for many areas and felt colder in a north-westerly wind. It started dry and bright on 12th but rain quickly spread from the west during the morning, clearing to the east late in the day. The 13th brought sunny spells and showers with a strong westerly wind, and thunder was reported in Lancashire and Norfolk. On 14th rain and strong winds spread north during the day; Preston Montford (Shropshire) recorded 36 mm of rainfall, and a gust of 73mph was recorded on the Isle of Wight. It remained unsettled on 15th with rain spreading from the south to reach northern areas by evening, and windy again with a gust of 72 mph on the Isle of Wight.
16th to 24th:
The 16th started bright but showers broke out in the afternoon with thunder for central areas. The 17th started dry and bright, but a band of heavy rain moved up the east coast with 33 mm recorded at Loftus (Cleveland). Heavy rain in northern areas on the morning of 18th cleared away to the west during the afternoon. It was brighter on 19th although the south coast saw pulses of rain during the morning. The 20th again was dry and bright. The 21st was cooler with a north-west wind, but mainly dry. This north-west wind strengthened on 22nd with showers for eastern coasts. The 23rd was a day of strong winds and frequent showers with Loftus recording a gust of 47 mph and thunderstorms in the Midlands and south-east. Another area of low pressure moved into eastern and central areas on 24th with strong winds and rain, gusts reaching 55 mph at Warcop (Cumbria).
25th to 31st:
High pressure edged in from the south, so 25th and 26th were dry and bright. A band of rain spread into the north-west on 27th, while central and eastern areas remained mainly dry. The 28th was wet for many areas, only eastern coastal areas remaining dry. A north-east wind on 29th saw rain spread from the east to reach the far west by late afternoon, Loftus recording 44 mm. The 30th saw patchy rain for eastern areas with the west remaining dry and bright. The 31st was dry with sunny spells, and warmer, reaching around 23 °C in some eastern areas.
Wales diary of highlights
May began with a spell of mainly dry and sunny weather, but after a week it became cooler and much more unsettled; the 14th was a particularly cold, wet day. The second half of the month was brighter for the most part, but only began to warm up at the end.
The mean temperature was 1.3 °C below the 1981-2010 average, making it the coldest May since 1996. Some parts of the country were rather wet, and the overall rainfall total was 131% of average. The sunshine total was exactly equal to the long-term average.
1st to 7th:
It was dry and sunny from 1st to 3rd, with high pressure to the south-west. The 4th was more overcast with some light showers. Though cloudy at times, 5th to 7th were more settled again.
8th to 16th:
On 8th a band of light rain moved north-east in the early hours, followed by sunshine and occasional light showers. Heavier rain crossed from the west during 9th, giving 33.6 mm at Capel Curig (Gwynedd), but sunshine followed in the west by late afternoon. The 10th and 11th had patchy rain or showers and some sunshine. The 12th was mainly overcast, with rain spreading from the west for a time. Sunshine and showers on 13th. Persistent heavy rain moved in from the south by mid-morning on 14th, but failed to reach the far north-west; Pembrey Sands (Dyfed) recorded 72.0 mm. On 15th rain moved eastwards in the early hours, with sunshine and isolated showers to follow, then 16th was a day of sunshine and showers.
17th to 24th:
The 17th was mainly dry and sunny, but with isolated showers in the far south-west. It was dry on 18th with sunshine in the south but more cloud further north. Dry and sunny on 19th but again cloudier further north. The 20th was mainly cloudy, but brighter and warmer in the south-east with 19.6 °C at St Athan (South Glamorgan). Cooler on 21st and 22nd but still with some sunny spells. It was breezy on 23rd with sunshine and showers. The 24th had sunshine too, but more cloud and light showers inland.
25th to 31st:
Warmer, dry and sunny on 25th and 26th. Cloud and rain spread in from the north-west to all parts in the morning of the 27th. On 28th, more cloud and rain moved east to west, reaching the south-west by evening. Cloudy with patchy rain in the east but brighter to the west on 29th. The 30th and 31st were dry with sunny intervals and broken cloud. Mumbles (West Glamorgan) reached 21.0 °C on 31st.
Scotland diary of highlights
The first part of the month was very unsettled, and quite cold to begin with with sleet and snow across higher ground. There were a few warmer interludes during the month, but only between 24th and 26th was it reasonably settled.
The mean temperature was 0.4°C below the 1981-2010 average. It was a rather wet month, especially on the western side of the country, with 141% of average rainfall overall. The sunshine total was 88% of the long-term average, the dullest May in Scotland since 2003.
1st to 3rd:
There was rain in most areas on 1st but this gradually cleared later in the day. Further rain, heavy at times, fell on 2nd, with 64.2 mm recorded at Achnagart (Highland), and some sleet or snow on higher ground, but the south was drier with only a few scattered showers. Most of the country was wet and windy on 3rd, with snow further north and on higher ground.
4th to 20th:
Mostly dry in the south on 4th, but scattered showers north of the Central Belt. The north-west had some showers on 5th, and rain moved into the west in the evening. There were scattered showers on 6th, which died out before rain arrived in the north-west later in the day. Dry and bright on 7th, with 21.4 °C recorded at Kinlochewe (Highland). Rain spread across the country from the south-west on 8th but was patchy in the north. More rain in the south on 9th but mostly dry in the north. Dry and bright at first on 10th before rain gradually spread in from the west. Unsettled again on 11th with showers or longer spells of rain for most areas. Rain in the south on 12th cleared to the east later on, but more rain and heavy showers pushed in from the west in the evening. It was wet again in the north-west on 13th with frequent blustery showers, heavy at times, with 58.4 mm recorded at Cassley (Sutherland), and also very windy with a gust of 55 mph recorded at Inverbervie (Angus). It remained unsettled on 14th with blustery showers across the country. Showery again for most areas on 15th with a band of rain affecting the south-east until the evening. Most areas began dry and bright on 16th but scattered showers in the west spread eastwards through the day. Dry and bright for most areas on 17th with just a few showers in the north, and warmer with a maximum of 17.6 °C at Glasgow, Bishopton (Renfrewshire). The south was very wet on 18th, with 32.6 mm recorded at West Freugh (Wigtownshire), but the north was drier until later in the day. The 19th was mostly dry, but overcast with mist or fog for many areas. Mostly dry on 20th but for some heavy thundery showers in the south and east later in the afternoon and evening, and warm in most areas with 22.3 °C at Strathallan (Perthshire).
21st to 23rd:
Scattered showers on 21st but many areas stayed dry. It was mainly dry in the south on 22nd but frequent showers in the north became more widespread through the day. Cold and windy on 23rd with frequent showers across the country, falling as hail, sleet or snow on higher ground.
24th to 26th:
Some rain at first on 24th in the south-east, but otherwise dry as a ridge of high pressure built across the country. Dry and warm for most of the country on 25th, with the exception of rain in the north-west. Mostly dry and warm again on 26th.
27th to 31st:
Rain for most areas on 27th, especially the south and west, as a front moved across the country. A few scattered showers on 28th, but dry for many areas until further rain spread to the south-west later on. Mostly dry on 29th with a few scattered showers. Rain on 30th especially in the east but becoming mainly dry. A weak front moved east across the country on 31st and brought mostly light rain to some areas.
Northern Ireland diary of highlights
The first two-thirds of the month were mainly unsettled, and quite cold at times with rain or showers. However, the latter part of the month was drier, warmer and sunnier.
The mean temperature was 0.6°C below the 1981-2010 average and it was the coldest May since 1996. It was a rather wet month, especially towards the north-west, with 144% of average rainfall overall. The sunshine total was 93% of the long-term average, the dullest May since 2003.
1st to 7th:
There was some light rain at first on 1st, clearing to leave some sunshine and lighter winds. Rain early then mainly dry but cloudy on 2nd with fresh southerly winds. It was unsettled but milder than of late on 3rd to 6th, with rain at night but drier by day, albeit cloudy. A ridge of high pressure on 7th brought a fine, dry day with temperatures reaching 20 °C in places.
8th to 20th:
Rain, some heavy, spread northwards on 8th, clearing to showers during the afternoon, with a total of 26.8 mm recorded at Caugh Hill (County Londonderry). Strong south-westerly winds on 9th brought periods of rain. The 10th was again unsettled with rain or showers for many areas but drier in the afternoon. Further rain on 11th cleared to give a mainly dry afternoon but more rain in the north in the evening. After a dry start on 12th, rain spread in quickly but cleared most areas during the afternoon. The 13th started dry and sunny but there were showers, some heavy, with hail in the afternoon. Scattered showers, occasionally of hail, continued through 14th, and 15th was another day of sunshine and scattered showers. After a dry, bright morning on 16th, there were showers in the afternoon. The 17th started dry and bright but a band of rain passed through quickly from the east. A dull start on 18th, and rain spread into northern parts in the early afternoon, becoming heavy and persisting through to the early hours of 19th, with rainfall totals of 40 mm recorded in the far north of Counties Antrim and Londonderry. Thereafter the day was dry and overcast, as was 20th until light rain spread into northern areas during the evening.
21st to 31st:
Pressure began to build, and 21st was brighter and mainly dry. The 22nd and 23rd saw scattered showers, and the northerly wind became strong on 23rd, gusting up to 55 mph at Orlock Head (County Down). The 24th and 25th were generally dry with plenty of sunshine. Dry at first on 26th, but with some heavy showers later. Rain or showers, heavy at times, persisted for much of 27th. A dry, sunny start on 28th, with showers in the afternoon. The 29th and 30th were dry and sunny, temperatures reaching 21 °C in the Belfast area on 29th, and any rain on 30th was restricted to northern areas later in the day. Rain in the morning of 31st cleared to leave a mainly fine day.