By Dr. Jeff Masters

June 2017 was the planet's third warmest June since record keeping began in 1880, said the National Oceanic and Atmospheric Administration's (NOAA) National Centers for Environmental Information on Monday. The National Aeronautics and Space Administration (NASA) rated June 2017 as the fourth warmest June on record. The only warmer Junes came in El Niño years: 1998, 2015 and 2016. Minor differences can occur between the NASA and NOAA rankings because of their different techniques for analyzing data-sparse regions such as the Arctic.

Global ocean temperatures last month were the third warmest on record for any June, according to NOAA, and global land temperatures were the fourth warmest on record. Global satellite-measured temperatures for the lowest 8 km of the atmosphere were the 12th warmest or 7th warmest for any June in the 39-year record, according to the University of Alabama Huntsville and Remote Sensing Systems, respectively.

Second-Warmest Year on Record Thus Far

Each of the first six months of 2017 have ranked among the top three warmest months on record, giving 2017 the second highest January—June period in the 138-year record: 0.91°C (1.64°F) above the 20th century average of 13.5°C (56.3°F). This is behind the record year of 2016 by 0.16°C (0.29°F), but beats third-place 2015 by 0.05°C (0.09°F). This near-record warmth is especially remarkable given the lack of an El Niño event this year. Global temperatures tend to be warmer during El Niño years, when the ocean releases more heat to the atmosphere.

Two Billion-Dollar Weather Disasters in June 2017

Two billion-dollar weather disaster hit the Earth last month, according to the June 2017 Catastrophe Report from insurance broker Aon Benfield: A $1.4 billion severe weather outbreak in the Midwestern U.S., and a $2.4 billion flood in the Yangtze River valley of China. By the end of June, Earth had registered twelve billion-dollar weather events for 2017, which is a typical number for this point in the year. The year that ended with the most billion-dollar weather disasters in records going back to 1990 was 2013, with 41, and that year had seventeen billion-dollar disasters by the end of June. Last year, there were already 21 billion-dollar weather disasters by the end of June (that year ended up with 31 such disasters). Here are this year's billion-dollar weather disasters through the end of June:

• Flooding, Peru, 1/1 – 4/1, $3.1 billion, 120 killed

• Severe Weather, Rockies, Plains, U.S., 5/8 – 5/11, $2.5 billion, 0 killed

• Flooding, China, 6/22 – 6/27, $2.4 billion, 31 killed

• Severe Weather, Plains, Southeast, Midwest U.S., 3/26 – 3/28, $2.2 billion, 0 killed

• Severe Weather, Midwest, Plains, Southeast U.S., 3/6 – 3/10, $2.1 billion, 0 killed

• Severe Weather, Midwest, Plains, Southeast MS Valley U.S., 4/28 – 5/01, $2.0 billion, 20 killed

• Tropical Cyclone Debbie, 3/27 – 4/5, $2.0 billion, 14 killed

• Drought, Somalia, Ethiopia, Kenya, 1/1 – 3/31, $1.9 billion, hundreds killed

• Severe Weather, South U.S., 2/27 - 3/2, $1.9 billion, 4 killed

• Severe Weather, Midwest U.S., 6/11, $1.4 billion, 0 killed

• Severe Weather, South U.S., 1/18 - 1/23, $1.3 billion, 21 killed

• Winter Weather, Plains, Southeast, Midwest, Northeast U.S., 3/13 - 3/15, $1.0 billion, 11 killed

No El Niño or La Niña Conditions Expected Into Winter

In its July 13 monthly advisory, NOAA's Climate Prediction Center stated that neither El Niño nor La Niña conditions were present in the Eastern Pacific (ENSO-neutral conditions existed), and these neutral conditions were expected to persist into the Northern Hemisphere winter (50 – 55 percent chance.) Sea surface temperatures (SSTs) in the benchmark Niño 3.4 region (in the equatorial Pacific) were about 0.5°C above average over the past week; SSTs of 0.5°C or more above average in this region are required to be classified as weak El Niño conditions, with the 3-month average SSTs holding at these levels for five consecutive months (with an accompanying El Niño-like atmospheric response). A surge of enhanced east-to-west blowing trade winds is predicted for the west-central Pacific over the next two weeks, and these stronger-than-average trade winds will interfere with any progression towards El Niño.

NOAA forecasters gave a 35 - 45 percent chance of an El Niño event occurring this year—a slight downgrade from their previous month's forecast, which gave a 35 - 50 percent chance. El Niño conditions tend to suppress Atlantic hurricane activity by bringing strong upper-level winds to the tropical Atlantic, creating high wind shear that tears storms apart. A reduction in the odds of El Niño boosts the odds of an active Atlantic hurricane season.

Arctic Sea Ice Extent Sixth Lowest on Record for June

Arctic sea ice extent during June 2017 had the sixth lowest extent in the 38-year satellite record, according to the National Snow and Ice Data Center. The total volume of the ice was at record low levels for June in 2017, and sea ice extent was virtually tied with the extent observed in June 2012, which ended up the lowest sea ice extent on record in September. The GFS model is predicting that low pressure and cloudy skies will predominate in the Arctic over the coming two weeks, which should keep ice extent from reaching a record low for the month.

Antarctic Sea Ice Extent Second Lowest on Record for June

Sea ice surrounding Antarctica was at unprecedented lows in recent months, setting an all-time monthly minimum extent record each month during the five-month period November 2016 – March 2017. However, monthly Antarctic sea ice extent in both April, May and June of 2017 were the second lowest on record for their respective months. But by the end of June 2017, Antarctic sea ice was at record-low extent again. A recent study by John Turner and colleagues links the recent Antarctic sea ice decline to a series of strong storms accompanied by long periods of warm winds from the north. These changing weather conditions are associated with large shifts in the Southern Annual Mode index.

Notable Global Heat and Cold Marks Set for June 2017

• Hottest temperature in the Northern Hemisphere: 53.7°C (128.7°F) at Ahwaz, Iran, June 29

• Coldest temperature in the Northern Hemisphere: -28.2°C (-18.8°F) at Summit, Greenland, June 6

• Hottest temperature in the Southern Hemisphere: 38.0°C (100.4°F) at Picos, Brazil, June 10

• Coldest temperature in the Southern Hemisphere: -83.9°C (-119.0°F) at Concordia, Antarctica, June 20

(Courtesy of Maximiliano Herrera.)

Major Weather Stations That Set (Not Tied) New All-Time Heat or Cold Records in June 2017

• Hanoi Lang Observatory (Vietnam) max. 41.5°C, June 3; beaten again with 41.8°C on June 4

• Hanoi Ha Dong (Vietnam) max. 42.0°C, June 3; beaten again with 42.5°C on June 4

• Lang Son (Vietnam) max. 40.8°C, June 4

• Dera Ismail Khan (Pakistan) max. 51.0°C, June 4

• Mezaira (United Arab Emirates) max. 52.5°C, June 16; New national record high

• Zahedan (Iran) max. 43.4°C, June 23

• Ahwaz (Iran) max. 53.7°C, June 29 ; New national record high (under standard conditions); also the new highest temperature ever recorded in Asia in June

(Courtesy of Maximiliano Herrera.)

Two All-Time National Heat Records Set in June 2017

As noted above, two nations (Iran and the United Arab Emirates) set their all-time records for hottest temperature in recorded history in June 2017. As of July 17, eight nations have set or tied all-time national heat records in 2017, and two have set or tied all-time cold records. 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.

All-Time National Heat Records Set or Tied in 2017:

• Iran: 128.7°F (53.7°C), at Ahwaz, June 29

• United Arab Emirates: 126.5°F (52.5°C), at Mezaira, June 16

• Oman: 123.4°F (50.8°C), at Qurayyat on May 30 and at Joba on May 31 (tie)

• Pakistan: 128.3°F (53.5°C), at Turbat on May 28 (tie)

• Guinea: 113°F (45.0°C), at Koundara, March 29 (tie)

• Ghana: 110.8°F (43.8°C), at Navrongo, March 26

• Chile: 113°F (45.0°C), at Cauquenes, January 26

• Cocos Islands (Australia): 91.2°F (32.9°C), at Cocos Island Airport, February 23

All-Time National Cold Records Set in 2017:

• United Arab Emirates: 22.3°F (-5.4°C) at Jabel Jais, February 3

• Qatar: 34.7°F (1.5°C) at Abu Samra, February 5

Reposted with permission from our media associate Weather Underground.