May 2018: Earth's 4th Warmest May on Record

June 18, 2018, 3:45 PM EDT

article image
Above: The deadliest disaster of May 2018 was an outbreak of severe thunderstorms and dusty downburst winds that killed 143 people in northern India on May 2-3. Separate severe thunderstorm outbreaks and resulting windstorms on May 6-9, May 13-16, and May 28-29 killed another 32, 95, and 54 people, respectively, in India. Above: Indian residents look at a wall damaged by high winds on Thursday, May 3, 2018, following the storm in the Agra district of northern India's Uttar Pradesh state on May 2. Image credit: AFP/Getty Images.

May 2018 was the planet's fourth-warmest May since record keeping began in 1880, said NOAA's National Centers for Environmental Information (NCEI) on Monday. NASA also rated May 2018 as the fourth-warmest May on record. NOAA found that the only warmer May months were 2016, 2015, and 2017, in that order, while NASA found the warmer Mays to be 2016, 2017, and 2014. Occasional differences in rankings between NASA and NOAA arise mostly due to how they handle data-sparse regions such as the Arctic, where few surface weather stations exist. The two agencies agreed that the planet's four warmest Mays in a century-plus of recordkeeping have all occurred in the past five years.

Global ocean temperatures during May 2018 were the fourth warmest on record, and global land temperatures were the seventh warmest on record, according to NOAA. Global satellite-measured temperatures in May 2018 for the lowest 8 km of the atmosphere were the ninth or seventh warmest in the 40-year record, according to the University of Alabama Huntsville (UAH) and RSS, respectively.

Graph of global temperatures for May through 2018
Figure 1. Departure of temperature from average for May 2018, the fourth-warmest May for the globe since record keeping began in 1880. Image credit: National Centers for Environmental Information (NCEI).
Map of global temperature departures from average, May 2018
Figure 2. Regional departures from average temperature for May 2018. Record warmth was observed over land across parts of North America and Asia and much of Europe, as well as across parts of the central North Atlantic and the subtropical North and South Pacific. It was the warmest May on record for the continent of Europe as a whole and for several European nations—including Belgium, Finland, Germany, Norway, and Sweden—as well as for the contiguous U.S. (see our national climate roundup for details). Cooler-than-average conditions prevailed across far eastern Canada and central Russia. Image credit: National Centers for Environmental Information (NCEI).

Two billion-dollar weather disasters in May 2018

Two billion-dollar weather-related disasters hit the Earth last month, according to the May 2018 Catastrophe Report from insurance broker Aon Benfield: a severe weather outbreak in the U.S. that cost $1.4 billion, and drought conditions in South Africa that have cost $1.1 billion since the beginning of the year. Here is the list of the nine billion-dollar weather disasters so far in 2018:

  1. Drought, Argentina and Uruguay, 1/1 – 3/31, $3.9 billion, 0 killed
  2. Winter Storm Riley, Eastern U.S., 3/1 – 3/3, $2.25 billion, 9 killed
  3. Winter Storm Friederike, Western & Central Europe, 1/18, $2 billion, 13 killed
  4. Winter Weather, China, 4/2 – 4/18, $1.5 billion, 0 killed
  5. Severe Weather, Rockies, Plains, Midwest, Northeast U.S., 5/12 – 5/16, $1.4 billion, 5 killed
  6. Winter Storms Eleanor & Carmen, Western & Central Europe, 1/1 – 1/4, $1.25 billion, 7 killed
  7. Drought, South Africa, 1/1 – 5/31, $1.1 billion, 0 killed
  8. Winter Storm Grayson, Central & Eastern U.S., 1/3 – 1/5, $1.1 billion, 22 killed
  9. Winter Weather, China, 1/24 – 1/29, $1.1 billion, 2 killed
Tree damage
May Billion-Dollar Disaster 1. An active weather pattern brought multiple clusters of severe thunderstorms with baseball-sized hail, straight-line winds gusting in excess of 70 mph and isolated tornado touchdowns from the Rockies to the Northeast on May 12 – 16, killing at least 5 and causing $1.4 billion in damages. A “derecho”--a long lived, fast-moving line of storms defined by straight-line winds gusting in excess of 60 mph—affected areas around New York City, Washington DC, and Baltimore, MD. Above: downed trees and power lines block Main Street South in Bridgewater, Conn., after severe storms rolled through the area Tuesday, May 15, 2018. Image credit: John Woike/Hartford Courant via AP.
May Billion-Dollar Disaster 2. Three years of unforgiving drought in South Africa have led to $1.1 billion in damages this year and endangered the municipal water supply of Cape Town. The feared “Day Zero”—the point when the reservoirs serving Cape Town drop below the minimum levels needed to provide water safely—was pushed back from April 2018 until at least 2019, though, thanks to drastic conservation measures imposed. Above, we see bare sand and dried tree trunks on May 10, 2017, at Theewaterskloof Dam, near Villiersdorp, about 40 miles east of Cape Town, South Africa. Significant winter rains have fallen in the Cape Town area since late April 2018, helping to push the dam's water level above 30% by mid-June. Additional rain is needed over the next few months to minimize the chance of another Day Zero threat in early 2019. See our post from June 13 for more details. Image credit: Rodger Bosch/AFP/Getty Images.

El Niño conditions expected later this year

An El Niño Watch is now in effect as sea surface temperatures (SSTs) in the eastern tropical Pacific Ocean continue to rise, said NOAA’s Climate Prediction Center (CPC) in its June 14 monthly advisory. Over the past week, sea surface temperatures (SSTs) in the benchmark Niño 3.4 region (in the equatorial Pacific) varied from near average to about 0.3°C above average, continuing this year's gradual warm-up from cool La Niña conditions that ended in April.

Odds for an El Niño event to form are predicted to increase as we head into the fall of 2018, with the June 14 CPC/IRI Probabilistic ENSO Forecast calling for a 51% chance of an El Niño event during the August-September-October peak of the Northern Hemisphere hurricane season. Those odds are up substantially from a 38% chance in the previous CPC/IRI outlook, which was issued in May. El Niño events typically reduce Atlantic hurricane activity, due to an increase in wind shear over the tropical Atlantic. The odds of El Niño are pegged at 64% for this coming winter (December-January-February), the time of year when El Niño events are typically at their strongest.

SST departures from average in Niño3.4 region, spring 2018
Figure 3. Sea surface temperatures (SSTs) in the benchmark Niño 3.4 region (in the equatorial Pacific) have been up to about 0.3°C above average over the past week, which qualifies as neutral conditons. Image credit: Levi Cowan,

Arctic sea ice falls to 2nd-lowest May extent on record

Arctic sea ice extent during May 2018 was the second lowest in the 40-year satellite record, behind the record set in May 2016, according to the National Snow and Ice Data Center (NSIDC). Ice-free waters extended all the way to a remarkable 82° N at the end of May north of Svalbard, where the average temperature for May 2018 was 6°C (11°F) above average.

Notable global heat and cold marks set for May 2018

Hottest temperature in the Northern Hemisphere: 51.0°C (123.8°F) at Jacobabad, Pakistan, 31 May
Coldest temperature in the Northern Hemisphere: -47.4°C (-53.3°F) at Geo Summit, Greenland, 9 May
Hottest temperature in the Southern Hemisphere: 38.7°C (101.7°F) at Walvis Bay, Namibia, 5 May
Coldest temperature in the Southern Hemisphere: -78.0°C (-108.4°F) at Concordia, Antarctica, 24 May
(Courtesy of Maximiliano Herrera.)

Major weather stations that set (not tied) new all-time heat or cold records in May 2018

Baharia (Egypt) max. 49.4°C,  22 May
Khajuraho (India) max. 48.6°C,  28 May
Durango (Mexico) max. 41.6°C,  29 May
Torreon (Mexico) max. 44.8°C,  31 May
Guadalajara (Mexico) max. 39.2°C,  31 May
Guanajuato (Mexico) max. 38.9°C,  31 May
(Courtesy of Maximiliano Herrera)

One all-time national heat record broken in 2018

So far in 2018, one nation has broken an all-time record for its hottest temperature in recorded history: Palau, which hit 95°F (35°C) at Koror on May 22. This beat the record set (most recently) back in February 2018: 93.9°F (34.4°C). No nations have set an all-time cold temperature record so far in 2018. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. I use as my source for international weather records researcher Maximiliano Herrera, one of the world's top climatologists, who maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records.

Twenty-one monthly national/territorial heat records so far in 2018

January: Marshall Islands
February: Marshall Islands, Falkland Islands, Kuwait, Qatar, Saudi Arabia, Palau.
March:  Marshall Islands, Qatar, Armenia, Madagascar, Pakistan, Iraq, UAE, Turkmenistan, Tajikistan, Uzbekistan.
April: Albania, Montenegro
May: Hong Kong, Norway
(Courtesy of Maximiliano Herrera.)

National monthly cold records in 2018: none

No national monthly records for cold were set in May 2018.

Continental/Hemispheric records in 2018

Highest temperature ever recorded in April in Asia: 50.2°C (122.4°F) at Nawabshah, Pakistan, 30 April

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

author image

Dr. Jeff Masters

Dr. Jeff Masters co-founded Weather Underground in 1995 while working on his Ph.D. in air pollution meteorology at the University of Michigan. He worked for the NOAA Hurricane Hunters from 1986-1990 as a flight meteorologist.

Recent Articles


Category 6 Sets Its Sights Over the Rainbow

Bob Henson

Section: Miscellaneous


Alexander von Humboldt: Scientist Extraordinaire

Tom Niziol

Section: Miscellaneous


My Time with Weather Underground (and Some Favorite Posts)

Christopher C. Burt

Section: Miscellaneous