The averaging period used for the following assessment was 1961-1990.
Mean temperatures close to average across most parts of the UK, making it the coldest May since 1996 for many areas. Rainfall totals again below average across the majority of England & Wales.
Tulloch Bridge recorded a temperature of -6.3 °C on 18th May, the lowest temperature so late in the season since 1956. Central London recorded 31.9 °C on 27th, the highest May temperature since 1947.
England and Wales diary of highlights
An unsettled first week but warm in the first few days. Drier second and third weeks, but with some overnight frosts. Unsettled through the last week with frequent showers. Hot on the 27th.
1st to 4th: A complex area of low pressure dominated the weather over the first few days of the month, initially to the west of the United Kingdom, but it then transferred east on the 3rd. There was some heavy rain and thunder across north Wales, the Midlands, East Anglia and Lincolnshire in the early hours of 1st. There were scattered thundery showers in the south-east and East Anglia later in the day. The temperature in central London reached 25.1 °C on 1st, a value not exceeded again over England and Wales until 26th. There were further thundery showers on 2nd and 3rd. An organised band of showers reached Cornwall at dawn on 2nd and spread north-east to exit north-east England in the evening. On 3rd organised thundery showers again moved from south-west England into Lincolnshire. There were showers in other parts too but south-east England stayed generally dry. On 4th a cold front cleared south-eastwards with some showery rain. It was evening before brighter skies reached the south-east.
5th to 9th: The 5th started chilly with a temperature of -0.9 °C at Redhill Aerodrome (Surrey) and a widespread grass (ground) frost across southern areas. Some rain edged south-east through the day, fragmenting overnight in southern counties. The 6th was a breezy day with sunny spells but Cornwall and west Devon were plagued by misty low cloud and some drizzle. Some showery rain spread into northern districts later. This rain cleared the south overnight, but not before giving some heavy rain in places, as a small low centre tracked south-east to be in the southern North Sea by the morning of the 7th. All parts then had a rather cold and breezy day with sunny spells and showers on 7th with some thunder and hail. A gust of 45 knots was recorded at Holbeach (Lincolnshire). There were further showers on 8th and 9th, again with hail and thunder in places. Benson (Oxfordshire) recorded -0.3 °C on the morning of the 8th. South-west England, the south coast and south Wales stayed mainly dry.
10th to 15th: Pressure rose during the 10th. There were some showers across eastern counties as a trough spread south. By 11th the high was established, giving many areas a couple of dry and largely sunny days. There was widespread ground frost early on 11th with an air frost in a number of places. Woburn (Bedfordshire) recorded -3.1 °C. Pressure was falling to the south and a chilly easterly wind picked up especially across southern England. Culdrose (Cornwall) recorded a gust of 41 knots on both 12th and 13th and the temperature only reached 10.0 °C at Cromer on 13th. Some rain edged into Cornwall and Devon on 13th and patchy rain spread to other southern counties as far east as East Sussex on 14th. There was a frost in some places again early on 15th, with -2.3 °C recorded at Benson. There was further rain over south-west England whilst northern England and north Wales had a sunny day.
16th to 18th: Rain spread south on a cold front on the 16th. There were some showers across north Wales in the morning on 17th and north-east England by afternoon. A short-lived ridge of high pressure brought a fine day to many on 18th but rain spread into south-west England and south Wales later.
19th to 23rd: Low pressure dominated the weather through this period. Rain in the south-west early on 19th spread to most places by dawn. Drier, brighter weather developed in the west but southern counties had some heavier rain by evening. The south still had some rain in the morning of the 20th. Heavy thundery showers developed from south-west England to north-east England and East Anglia. It was warm in the east with 20.5 °C at Coningsby (Lincolnshire). There were further showers between 21st and 23rd. A tornado was reported at Heachem (Norfolk) on 21st. On 23rd it was showery especially in the west and north. Shap Fell (Cumbria) recorded 19.6 mm of rain 0900 to 2100 UTC whilst more south-eastern parts of England were largely dry and bright.
24th to 27th: Fronts spread some rain eastwards on 24th but most places brightened up in the afternoon. Western and southern coasts had misty low cloud and some drizzle on 25th as a warm front moved north-east but it gave very little rain elsewhere. A weakening cold front in the west on 26th cleared the south-east in the evening and then another warm front moved north on 27th. Warm southerly winds on 27th gave a hot day to most parts. In central London the temperature reached 31.9 °C, the highest May temperature in the UK since 31st May 1947. There were some thundery showers across central southern England in the morning and these spread north to north-east England in the afternoon.
28th to 31st: A cold front brought fresher weather on 28th and strong winds especially to the west. Capel Curig (Gwynedd) recorded a gust of 54 knots. It was dry with sunny spells in most parts but especially the east. Winds were lighter the following day and most places were dry. An area of heavy rain over the far south-east and East Anglia overnight and early on 30th gave 16.4 mm of rain at Wattisham (Suffolk) in the 12 hours to 0900 on 30th. Showers developed in many places during the morning but especially the east. These were heavy and thundery in places and tornadoes were reported around Soham (Cambridgeshire) and Newmarket (Suffolk) in the late morning. There were a few showers on 31st to round off the month.
Scotland diary of highlights
Changeable and unsettled conditions dominated May with the notable exception of a fine spell from the 10th to the 15th. This ensured that sunshine totals were close to or above average, but cyclonic episodes during the second half of the month made it wet in most places. Temperatures were close to average.
A large area of low pressure transferred north-east across Scotland between the 1st and the 3rd. Rain bands moving north across the country were followed by showers.
From the 4th to the 9th a north-westerly airstream covered Scotland between an anticyclone in mid-Atlantic and a depression close to Scandinavia. A ridge gave a fine day in the south-east on the 4th before frontal cloud and slight rain passed over Scotland during the night. The next few days brought sunny periods and showers and it became progressively colder. On the 7th the maximum temperature at Fair Isle was 7 °C and snow fell on hills.
An anticyclone moved over Scotland from the west on the 10th and remained slow moving for several days. Most places enjoyed a spell of sunny weather with a large diurnal range of temperature. On the 13th a minimum of -3 °C at Altnaharra was followed by a maximum of 17 °C in the afternoon. Daytime temperatures continued to rise with 21 °C recorded at Strathallan on the 15th.
A cold front moving down from the north introduced Arctic air on the 17th and brought a sudden drop of maximum temperature with values of 6 °C at some northern stations. After some showers the next day a clear night with light winds allowed minima of -6 °C to be recorded in some Highland glens (coldest temperature so late in the season since 1956). This was followed by a sunny day in the north-east.
A return to unsettled conditions began on the 17th as a large area of low pressure became slow moving to the west of Scotland. Fronts pushing north brought much rain to the south-west with 42 mm at Lochranza. The fronts cleared northwards the next day and it became much warmer with the temperature rising to 19 °C at Kinloss and Altnaharra. A regime of sunny periods and showers prevailed for the next few days.
Two major depressions moved north-east close to the west of Scotland between the 25th and 28th. The associated fronts brought much cloud and rain, with the biggest downpour occurring in the south-west. On the 25th Sloy recorded 55 mm and Saughall in Ayrshire 43 mm. After a respite for most areas on the 26th, there was further cloud, rain and strong winds on the 17th and 28th. At Port Ellen and Charterhall (in the Borders) gusts reached 56 m.p.h. and 54 m.p.h. respectively.
During the last three days the depression moved away and a weakening north-westerly airstream brought sunny periods and showers. There were few showers in the south-west, but further rain arrived here overnight on the 31st
Northern Ireland diary of highlights
Temperatures overall were close to average for the month, making it the coolest May since 1996. Rainfall values finished above average, after a very wet second half.
The first week of the month was a mixture of sunny spells and scattered showers. Some of the showers were quite heavy on the 1st and 2nd with local thunder. In sunny periods it was pleasantly warm, with day-time temperatures around 17 or 18 °C. Thereafter it became somewhat cooler and the 7th had some significant hail showers.
The second week was dominated by high pressure and all areas had a good deal of dry and sunny weather. Indeed many areas recorded around 100 hours of bright sunshine in a 10 day period. It was rather cool though and the period was characterised by some cold nights with widespread frosts. Temperatures on the early morning of the 10th fell to between -1 and -3 °C. The period between the 11th and the 14th was particularly fine with almost unbroken sunshine in some areas.
The fine spell ended as the second half of the month began and indeed the weather became unsettled, cool and often wet through the second fortnight. Showers or longer periods of rain affected all areas and the bulk of the month's rain fell between the 17th and the 28th. The 22nd was notable for some heavy and thundery rain in the afternoon with some areas seeing 10 mm of rain in just two hours. The pattern was repeated in some areas on the 23rd as well. The 25th was another very wet day with many areas having between 20 and 25 mm of rain.
The 28th saw a deep low pressure area move to the north of Ireland and this gave an unusually windy day for late May with strong to gale force south-west winds. Gusts over 50 m.p.h. occurred over exposed coasts. This moved away and the 29th and 30th were drier, brighter days and apart from a few well-scattered showers, the month ended on a slightly sunnier and warmer note.