El Nino conditions were established in May with oceanic and atmospheric indicators showing a clear signal (BoM ENSO wrap up).

There was record May heat in parts of Europe. At times, temperatures were the highest May temperatures reported anywhere on the continent.

Spain had its second warmest May with temperatures particularly high in the south. Stations broke May records and neared all-year records. It was also the driest May in the series which started in 1947. The total recorded precipitation was 17mm; the normal average for the month is 61mm. At Sevilla San Pablo, maximum temperatures exceeded 25degC every day in May and 24 days exceeded 30degC, a new record for that station. Portugal’s mean maximum temperature was 25.46degC, 4.5degC above normal and the highest in the national series, which begins in 1931. Minimum temperatures were the second highest on record.

Early in the month, southerly winds brought warm air from Africa into Europe and high temperatures o Sardinia and Catania Sigonella on Sicily on 5 May. On 14 May, exceptional temperatures were reported in Spain and Portugal. In Portugal, 40degC was reported at Beja, which had 19 days when the maximum temperature exceeded 30degC (usually only 5 days exceed this threshold in May). The maximum temperature recorded at Lanzarote airport on 13 May exceeded the previous record by 6degC, reaching 42.6degC.

Alaska was “freakily” warm – its famous “ice road” melted a month early – and it was the warmest May in the 91 year record for the state. Both Barrow and Juneau (at opposite ends of the state) had record warmth for the month. Connecticut, Massachusetts, New Hampshire and Rhode Island were each record warm.

From 21-31 May, a heatwave affected India and there are reports of more than 2000 fatalities. May is generally the hottest month of the year in India before the Monsoon rains bring some respite.

Monthly mean temperatures were significantly above normal all over Japan and broke the record-high for May since 1946 in northern and eastern Japan. Monthly sunshine durations were also broken for May on the Pacific side of northern Japan and on the Sea of Japan side of eastern Japan. South Korea had its highest May mean temperature (though neither min nor max were individually a record) since 1973 when records began.

The north of Europe was cold and wet. Monthly precipitation for Norway was 175% of normal, the second wettest May in the national series which starts in 1900. The wettest was May 1949. In Sweden, several stations with records longer than 100 years, reported their highest May totals. In Stockholm, it was the wettest May in 200 years. Iceland was rather cool and Greenland had its coldest May in some parts (Danmarkshavn) since records began in the 1940s. Austria had one of its gloomiest May months in the last 25 years. Rainfall was 50% above average for the country. Ireland described May as extremely wet, cold and dull in places. At Malin Head, 137mm of rain fell, which was 235% of average. The wettest May in 123 years and the second wettest since records began. Other stations were less extreme. In many parts, it was the coldest May in 19 years. Heavy rainfall and strong winds from 19 to 23 May 2015 Slovenia. Some stations recorded more than a month’s rainfall in four days.
Slovakia had unusually high rainfall totals on the northern side of the Tatras. Daily rainfall totals were the highest in at least half a century at some locations.

Areas of northern South America, central America and the Caribbean islands were drier than average including Puerto Rico. Other dry areas included south east Asia and Oceania. Despite being dry overall, parts of Colombia saw heavy rain in May that caused mudslides that left 92 dead.

Areas that were wetter than average also included central south America and parts of south east China. In southern and central China, flooding and mudslides killed around 35 people. In Tajikistan, prolonged rain caused flooding and mudslides from 11-13 May. Around 1776 people were severely affected.

The May precipitation total for the contiguous U.S. was 4.36 inches, 1.45 inches above average and the wettest May and wettest month in the 121-year national series. The previous wettest May was in 1957 with 4.24 inches. The previous wettest month was October 2009 at 4.29 inches.

It was the wettest May on record for Oklahoma and Texas. According to data compiled by the state’s climatologist, John Nielsen-Gammon, the state has received an average 7.54 inches of rain, exceeding the previous record of 6.66 inches for June 2004. 7.54 inches of rain for Texas is equivalent to about three months of discharge from the Mississippi River. Colorado was also record wet for the month.

The heavy precipitation during May essentially ended the multi-year drought that has affected the Southern Plains since 2011. At the beginning of June, only 0.6% of Texas and 0.0% Oklahoma were in drought. This was the first time since 2010 that the drought footprint in both states has been this low.

The pile of snow that had been cleared from the streets of Boston persisted into May.

Arctic sea ice extent 3rd smallest. Antarctic sea ice extent highest on record again.

Sundry summaries:

Australia – http://www.bom.gov.au/climate/current/month/aus/summary.shtml
NZ – http://www.niwa.co.nz/climate/nzcu/new-zealand-climate-update-192-june-2015/current-climate-%E2%80%93-may-2015
Russian May summary – http://www.meteoinfo.ru/climate/climat-tabl3/-2015-/11199–2015-
Austria – http://www.zamg.ac.at/cms/de/klima/klima-aktuell/monatsrueckblick/unwetterbericht/
UK – http://www.metoffice.gov.uk/climate/uk/summaries/2015/may
France – http://www.meteofrance.fr/actualites/25525587-un-printemps-doux-et-sec

Tropical storms

N Atlantic – Tropical Storm ANA 08-11 MAY Tropical Storm Ana is the second earliest landfalling tropical cyclone on record for the United States. Only the Groundhog Day tropical storm that struck Florida in February 1952 was earlier. http://www.ncdc.noaa.gov/sotc/national/201505
NW Pacific – Super Typhoon-5 NOUL 03-12 MAY
Super Typhoon-5 DOLPHIN 07-19 MAY
S Indian – Cyclone-4 QUANG 28 APR-01 MAY Tropical cyclone Quang produced widespread moderate falls in the Pilbara and adjacent areas of Western Australia at the start of the month http://www.bom.gov.au/announcements/sevwx/wa/watc20150427.shtml