April 2016: Earth's 12th Consecutive Warmest Month on Record

Keeping a year-long string of record-warm months going, April 2016 was by far the planet's warmest April since record keeping began in 1880, said NOAA's National Centers for Environmental Information (NCEI) on Wednesday. In the NOAA database, April 2016 came in a full 1.10°C (1.98°F) warmer than the 20th-century average for April of 13.7°C (56.7°F), as well as 0.28°C (0.50°F) above the previous record for April, set in 2010. This is a huge margin for breaking a monthly global temperature record, as they are typically broken by just a few hundredths of a degree. The only months with larger warm departures from average were March and February 2016 and December 2015. NASA also reported the warmest April in its database (1.11°C above the 1951-1980 average), and the margin it broke the previous record by--0.24°C--was the largest margin ever recorded to break the April record by. The seven warmest months in NASA's database, relative to average, have been the past seven months (with data going back to 1880); these are the only months in the database with readings of at least 1.0°C above average.

April 2016 marked the twelfth consecutive month that the monthly temperature record was broken and the seventeenth consecutive month (since December 2014) that the monthly global temperature ranked among the three warmest for its respective month in the NOAA database. Both global ocean and global land temperatures were the warmest on record for any April. Global satellite-measured temperatures in April 2016 for the lowest 8 km of the atmosphere were the 2nd warmest for any April in the 38-year record, and the fourth-largest warm departure from average for any month, according to the University of Alabama in Huntsville (UAH). This breaks a string of six consecutive months the UAH database had registered a record monthly high.

The impressive global warmth in recent months is due to the steady build-up of heat-trapping greenhouse gases due to human activities, plus a spike due to a large amount of heat being released from waters in the Eastern Pacific due to the powerful 2015-16 El Niño event. This event peaked in December, but the warmest atmospheric readings (relative to average) usually lag the peak oceanic temperatures by a few months. NOAA’s global surface temperature for the year so far (January-April 2016) is an astounding 0.30°C (0.54°F) warmer than the previous record, set in 2015 (see Figure 2).



Figure 1. Departure of temperature from average for April 2016, the warmest April for the globe since record keeping began in 1880. Record warmth was observed over several land areas on Earth as well as most of the Indian Ocean, with especially warm readings over northern South America, northeast Africa, southeast Europe, southeast Asia, northern Australia, southern Greenland, and southern Alaska. Image credit: National Centers for Environmental Information (NCEI).




Figure 2. Departure from average for the global January-through-April temperature for the years 1880 - 2016. This year has seen by far the warmest temperatures on record for each of the four months. Image credit: NOAA/National Centers for Environmental Information (NCEI).

Will 2016 set another record high?
It’s increasingly probable that 2016 will eclipse 2015 as the warmest year in global temperature records that go back to 1880. When major El Niño events straddle two calendar years, the second year is often the warmer one globally, as there is a lag of several months between the peak oceanic and atmospheric warming. Here’s one way to look at the question: how cool would the rest of 2016 need to be to prevent an annual record? Let’s assume that a good analog for this year is 1998, when a very strong El Niño waned quickly in northern spring and was succeeded by a moderately strong La Niña by year’s end. That year, the departure in average global temperature was 0.71°C for January through April, and it dropped to 0.59°C for May through December. If we were to experience a similar drop in global temperature later this year—which is possible if we transitioned to a moderate La Niña, as predicted by several models—then the departure from average for the last eight months of the year could be in the neighborhood of 1.02°C. In that case, 2016 will still cruise handily to the title of warmest year on record. The drop from Jan-Apr to May-Dec would need to be twice as large this year as it was in 1998 in order to put this year’s annual average below that of 2015. Small wonder, then, that NASA/GISS director Gavin Schmidt has laid 99% odds on this year becoming the warmest in global records.




Figure 3. Global temperature in the year 2016 has left all recent years in the dust for the period January through April. Image credit: Climate Central.

El Niño on its way out
El Niño conditions weakened to the "moderate" classification during April 2016, and El Niño continues to weaken rapidly. The event peaked in strength in late November 2015, when the weekly sea surface temperatures (SSTs) in the so-called Niño3.4 region (5°S - 5°N, 120°W - 170°W) peaked at a record 3.1°C above normal. By the week of May 16, 2016, the Niño3.4 SST anomaly had fallen to 0.6°C above average--barely above the 0.5°C threshold to be considered an El Niño. NOAA expects a transition to neutral conditions during early summer 2016, with a 65% chance of a transition to La Niña conditions by the August-September-October peak of the Atlantic hurricane season.

Arctic sea ice at its lowest April extent on record—and still plummeting
A key U.S. satellite sensor used to monitor sea ice extent failed in early April, and the National Snow and Ice Data Center (NSIDC) was unable to provide an estimate of the April sea ice extent in the Arctic. However, satellite data from the Danish Meteorological Institute, using a different instrument, showed that last month’s sea ice extent in the Arctic was the lowest for April across the 38-year satellite record. The unprecedented mid-spring melt is barreling ahead this month. Provisional data for early May from a replacement sensor now being calibrated by NSIDC closely resembles the data shown below in Figure 4, as well as analyses from the Japan Aerospace Exploration Agency (JAXA). “We are at a record low for this time of year,” confirmed Mark Serreze (NSIDC) in an email. We will have much more on this spring’s Arctic ice loss in an upcoming post.


Figure 4. Arctic sea ice extent through May 16, 2016. Arctic sea ice has been at record low levels from early April through mid-May 2016. Image Credit: Danish Meteorological Institute.

Three billion-dollar weather disasters in April 2016
According to the April 2016 Catastrophe Report from insurance broker Aon Benfield, three billion-dollar weather-related disasters hit the planet in April--two severe weather outbreaks in the U.S., and a flood disaster in South America. In addition, two other disasters from earlier in the year (Tropical Cyclone Winston in Fiji and a March 22-25 severe weather outbreak in the U.S.) accumulated enough damage claims to be rated billion-dollar disasters by the end of April. Between January - April 2016, there were twelve billion-dollar weather disasters. This is well ahead of pace of nine such disasters in January - April 2013--the year that ended up with the most billion-dollar weather disasters on record: 41. Last year had only five billion-dollar weather disasters through April. Here is the tally of billion-dollar weather disasters for January - April 2016:

1) Drought, Vietnam, 1/1 - 5/1, $6.7 billion, 0 killed
2) Severe Weather, Plains-Southeast U.S., 4/10 - 4/13, $2.75 billion, 1 killed
3) Winter Weather, Eastern U.S., 1/21 - 1/24, $2.0 billion, 58 killed
4) Winter Weather, East Asia, 1/20 - 1/26, $2.0 billion, 116 killed
5) Severe Weather, Rockies-Plains-Southeast-Midwest U.S., 3/22 - 3/25, $1.75 billion, 0 killed
6) Drought, Zimbabwe, 1/1 - 3/1, $1.6 billion, 0 killed
7) Flooding, Argentina and Uruguay, 4/4 - 4/10, $1.3 billion, 0 killed
8) Severe Weather, Plains-Midwest-Southeast-Northeast U.S., 3/4 - 3/12, $1.25 billion, 6 killed
9) Severe Weather, Plains-Midwest-Southeast-Northeast U.S., 2/22 - 2/25, $1.2 billion, 10 killed
10) Severe Weather, Plains-Rockies U.S., 4/15 - 4/19, $1.0 billion, 9 killed
11) Severe Weather, U.S., 3/17 - 3/18, $1.0 billion, 0 killed
12) Tropical Cyclone Winston, Fiji, 2/16 - 2/22, $1.0 billion, 44 killed

And here are the three disasters from April 2016:


Disaster 1. Heavy rains caused extensive flash flooding across parts of Texas on April 18, killing eight and leading to more than 1,800 water rescues in the greater Houston metropolitan area. The same storm also brought heavy snow and severe thunderstorms from April 15 - 19 to parts of the Rockies and Plains, killing one person. Damage was estimated at $1.0 billion. In this image, we see Kaicee Crowley walking through floodwaters to get belongings out of her stranded car at the North Main Street exit off I-45 in Houston on April 18, 2016, as White Oak Bayou came over its banks and floods the freeway. Image credit: Karen Warren/Houston Chronicle via AP.


Disaster 2. Severe thunderstorms caused catastrophic hail damage across parts of the Plains and Southeast from April 10 - 13, killing at least one person and injuring dozens more. The Dallas-Fort Worth and San Antonio metro regions in Texas were the hardest hit, where softball- and baseball-sized hail fell. Damage was estimated at $2.75 billion. In this photo, we see an impressive shelf cloud from a thunderstorm over Royce City, Texas, on April 11, 2016. Image credit: wunderphotographer Gweduc.


Disaster 3. Torrential rains led to severe flooding across portions of Argentina and Uruguay from April 4 - 10. No serious injuries or fatalities were reported. Hardest hit was northeast Argentina, where seven-day rainfall totals tallied as much as 750 millimeters (29.53 inches] in parts of the provincial regions of Entre Rios, Corrientes, Santa Fe, Chaco, Formosa, and Santiago del Estero. More than 15,000 people were affected, with most of the damage occurring along the overflowing Paraná and Salado rivers. Substantial damage occurred to 4 percent of the country’s soybean crop. Total economic losses to agriculture in Argentina alone were estimated at $1.3 billion. In this image, we see flooding in Villa Paranacito, Entre Rios, Argentina, on April 28, 2016. (AP Photo/Natacha Pisarenko)

Notable global heat and cold marks set for April 2016
Hottest temperature in the Northern Hemisphere: 48.5°C (119.3°F) at Titlagarh, India, 24 April
Coldest temperature in the Northern Hemisphere: -46.2°C (-51.2°F) at Geo Summit, Greenland, 7 April
Hottest temperature in the Southern Hemisphere: 43.2°C (109.8°F) at Onslow Airport, Australia, 2 April
Coldest temperature in the Southern Hemisphere: -79.1°C (-110.4°F) at Concordia, Antarctica, 24 April
(Courtesy of Maximiliano Herrera.)

Major weather stations that set (not tied) new all-time heat or cold records in April 2016
Record heat waves in Southeast Asia and Africa caused a remarkable five nations to set all-time heat records in April 2016 (see below). The excessive heat gives us an uncommonly long list of all-time local heat records in more than a dozen nations to report:

Keningau (Malaysia) max. 37.3°C, 7 April
Batu Embun (Malaysia) max. 38.6°C, 9 April; followed by 39.2°C on 10 April
Bua Chum (Thailand) max. 43.2°C, 10 April
Surin (Thailand) max. 42.2°C, 10 April; followed by 42.8°C on 11 April; followed by 42.9°C on 12 April; followed by 43.1°C on 17 April
Chok Chai (Thailand) max. 41.3°C, 10 April; followed by 42.5°C on 11 April
Tak Fa (Thailand) max. 41.6°C, 10 April; followed by 41.7°C on 22 April
Nang Rong (Thailand) max. 41.9°C, 10 April; followed by 42.8°C on 11 April; followed by 43.0°C on 12 April
Banteay Ampil (Cambodia) max. 42.2°C, 11 April: New national record high for Cambodia
Saravanh (Laos) max. 41.2°C, 11 April; followed by 41.5°C on 16 April
Nakhon Ratchasima (Thailand) max. 43.2°C, 11 April
Tha Phra (Thailand) max. 42.7°C, 11 April
Kosumphisai (Thailand) max. 42.5°C, 11 April
Ubon Ratchathani (Thailand) max. 42.5°C, 11 April; followed by 42.6°C on 15 April
Roi Et (Thailand) max. 42.3°C, 11 April
Aranyaphrathet (Thailand) max. 42.2°C, 11 April
Nan (Thailand) max. 42.2°C, 11 April; followed by 42.4°C on 12 April; followed by 43.3°C on 14 April
Nong Phlub (Thailand) max. 42.0°C, 11 April
Chainat (Thailand) max. 41.8°C, 11 April
Surat Thani (Thailand) max. 41.3°C, 11 April
Kho Hong (Thailand) max. 39.9°C, 11 April
Hat Yai (Thailand) max. 39.3°C, 11 April; followed by 39.7°C on 28 April
Koh Samui (Thailand) max. 38.0°C, 11 April
Pattani (Thailand) max. 38.3°C, 12 April; followed by 38.5°C on 19 April; followed by 38.7°C on 21 April
Lom Sak (Thailand) max. 41.9°C, 12 April; followed by 42.0°C on 18 April
Sakon Nakhon (Thailand) max. 42.5°C, 12 April
Nakhon Sawan (Thailand) max. 43.2°C, 12 April; followed by 43.4°C on 19 April
Seno (Laos) max. 42.3°C, 12 April: New national record high for Laos
Long Island (India) max. 37.6°C, 12 April
Sagaing (Myanmar) max. 43.8°C, 12 April
Phonm Penh (Cambodia) max. 41.0°C, 13 April
Temerloh (Malaysia) max. 38.8°C, 13 April
Dori (Burkina Faso) max. 47.5°C, 13 April: New national record high for Burkina Faso
Dedougou (Burkina Faso) max. 45.2°C, 13 April
Boromo (Burkina Faso) max. 44.2°C, 13 April
Tillabery (Niger) max. 47.0°C, 13 April
Bougouni (Mali) max. 44.0°C, 13 April
Banjul (Gambia) max. 44.4°C, 14 April
Mersing (Malaysia) max. 37.4°C, 14 April
Malaybalay (Philippines) max. 36.4°C, 15 April
Kozhikode (India) max. 39.1°C, 15 April; followed by 39.2°C on 30 April
Preah Vihea (Cambodia) max. 42.6°C, 15 April: New national record high for Cambodia
Attapeu (Laos) max. 42.0°C, 15 April
Houei Sai (Laos) max. 40.8°C, 15 April; followed by 41.0°C on 28 April
General Santos (Philippines) max. 39.4°C, 16 April
Hanimaadhoo (Maldives) max. 34.9°C, 16 April: New national record high for the Maldives; followed by 35.0°C on 30 April
Walvis Bay Airport (Namibia) max. 42.8°C, 16 April
Danxian (China) max. 40.4°C, 17 April
Changjiang (China) max. 40.5°C, 17 April
Satun (Thailand) max. 39.6°C, 20 April
Kottayam (India) max. 39.9°C, 20 April
Car Nicobar (India) max. 35.4°C, 22 April
Bengaluru (India) max. 39.2°C, 24 April
Mysore (India) max. 39.9°C, 24 April
Palakkad (India) max. 41.9°C, 26 April
Phetchabun (Thailand) max. 43.3°C, 26 April
Bhumibol Dam (Thailand) max. 43.9°C, 27 April
Sayabouri (Laos) max. 40.8°C, 27 April
Cannur (India) max. 39.2°C, 27 April
Jaffna (Sri Lanka) max. 37.0°C, 27 April
Mae Hong Son (Thailand) max. 44.6°C, 28 April: New national record high for Thailand
Yalla (Thailand) max. 40.1°C, 28 April
Magwe (Myanmar) max. 46.5°C, 29 April
Yamethin (Myanmar) max. 45.0°C, 29 April
Thayawady (Myanmar) max. 43.9°C, 29 April
Loikaw (Myanmar) max. 39.5°C, 29 April

(Courtesy of Maximiliano Herrera.)

Five all-time national heat records set in April 2016
From January through May 16, 2016, a total of nine nations or territories tied or set all-time records for their hottest temperature in recorded history--which is a huge number of records for so early in the year. One all-time cold temperature record has been set so far in 2016 (in Hong Kong.) "All-time" record here refers to the warmest or coldest temperature ever reliably reported in a nation or territory. The period of record varies from country to country and station to station, but it is typically a few decades to a century or more. Most nations do not maintain official databases of extreme temperature records, so the national temperature records reported here are in many cases not official. Our data source is 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. Here are 2016's all-time heat and cold records as of May 16:

Maldives set its all-time hottest record on April 30, 2016, when the mercury hit 35.0°C (94.8°F) at Hanimaadhoo.

Thailand set its all-time hottest record on April 28, 2016, when the mercury hit 44.6°C (112.3°F) at Mae Hong Son.

Cambodia set its all-time hottest record on April 15, 2016, when the mercury hit 42.6°C (108.7°F) at Preah Vihea.

Burkina Faso set its all-time hottest record on April 13, 2016, when the mercury hit 47.5°C (117.5°F) at Dori.

Laos set its all-time hottest record on April 12, 2016, when the mercury hit 42.3°C (108.1°F) at Seno.

Vanuatu in the South Pacific set its all-time hottest record on February 8, 2016, when the mercury hit 36.2°C (97.2°F) at Lamap Malekula.

Tonga set its all-time hottest record on February 1, 2016, when the mercury hit 35.5°C (95.9°F) at Niuafoou.

Wallis and Futuna Territory (France) set a new territorial heat record with 35.8°C (96.4°F) on January 10, 2016 at Futuna Airport. This is the second year in a row that Wallis and Futuna has beaten its all-time heat mark; the previous record was a 35.5°C (95.9°F) reading on January 19, 2015 at the Futuna Airport.

Botswana set its all-time hottest record on January 7, 2016, when the mercury hit 43.8°C (110.8°F) at Maun.

Hong Kong Territory (China) set its all-time coldest mark on January 24, 2016, when the mercury dipped to -6.0°C (21.2°F) at Tai Mo Shan.

Heat records continue to tumble across India
Wednesday, May 18, brought the hottest reliably measured temperature on record for a populated location in India, as Phalodi soared to 50.5°C (122.9°F). The hottest temperature in India’s history as recognized by the India Meteorological Department is just 0.1°C warmer: 50.6°C (123.1°F) at Alwar, Rajasthan, on May 10, 1956. There was also a 50.6°C (123.1°F) measurement taken at Pachpadra (an uninhabited saline depression) on May 25, 1886. According to Herrera, the Pachpadra reading in 1886 is not that reliable, because the screen used on the instrument shelter was of questionable quality. He also believes that the official record at Alwar is junk—that record was set during what was not an exceptional heat wave, just a few months after the station was installed. Temperatures were constantly overestimated by 5 - 6°C during the first few years of operation of the station, after which it was probably fixed, since its temperatures fell in line with neighboring stations.
Update: On Thursday, May 19, Phalodi reached a high of 51.0°C (123.8°F]--a clear record for the highest temperature ever observed in India.

Jeff Masters and Bob Henson