Record warm temperatures across a swath of the northeast, central and southwest Pacific Ocean basins, as well as parts of the western Atlantic Ocean, western Caribbean Sea, southern Mexico, northern Scandinavia, Barents Sea, northern and central Argentina contributed to the anomalous January-June 2015, according to NOAA.
Hottest months, global heat waves - May 2015 hottest/wettest month
The first 6 months of 2015 have been the hottest on record
People sunbathe in a beach in Barcelona, Spain, Friday, May 15, 2015. The Iberian Peninsula has experienced record high temperatures for May as thermometers shot up to levels normally only seen in midsummer. (AP Photo/Emilio Morenatti)
Jordyn Chin, 5, plays in the fountain at Dilworth Park Friday, June 12, 2015, in Philadelphia. Officials say Philadelphia's public schools are closing early due to heat. The National Weather Service predicts a high of 93 degrees in the city. (AP Photo/Matt Rourke)
FILE - In this Sunday, May 31, 2015 file photo, an Indian man rests in front of an air cooler to cool himself on a hot summer day in Hyderabad, in the southern Indian state of Telangana. Isolated thundershowers have failed to break a raging heat wave in the southern Indian states of Andhra Pradesh and Telangana, claiming dozens of lives over the weekend and raising the overall death toll to more than 2,000 since mid-April. (AP Photo/Mahesh Kumar A., File)
Laborers cover their faces as they ride a truck on a highway in Cairo, Egypt, Wednesday, May 27, 2015, during a sandstorm and a heat wave. Temperatures are soaring across the Middle East, with winds and sandstorms driving people indoors as unlucky pedestrians try to shield themselves from the sun with books, newspapers or anything they can find. (AP Photo/Mosa'ab Elshamy)
An Indian man bathes in water from a roadside tap in Kolkata, India, Sunday, May 31, 2015. Heat-related conditions, including dehydration and heat stroke, have killed more than 2,000 people since mid-April in the southern Indian states of Andhra Pradesh and Telangana, according to state officials. (AP Photo/ Bikas Das)
Indian boys cool themselves at a fountain on a hot day in New Delhi, India, Monday, May 18, 2015. Intense heat-wave continues to grip several parts of north India with most of the cities crossing 40 degrees Celsius (104 degrees Fahrenheit) mark. (AP Photo/Tsering Topgyal)
Indian men cover their head with handkerchief as they walks in the rain at Nehru Zoological Park in Hyderabad, India, Friday, May 29, 2015. According to weather reports, the heat wave scorching vast parts of the country would continue for a few more days though cloudy skies and sporadic showers have brought relief to the people in some states. (AP Photo/Mahesh Kumar A.)
An Indian boy jumps into the Ranbir water canal to cool on a hot summer day in Jammu, India, Monday, May 25, 2015. Severe heat wave conditions continue to prevail at several places in northern India with temperatures reaching 48 degrees Celsius (118 degrees Fahrenheit). (AP Photo/Channi Anand)
An Indian child plays in front of a water sprinkler to cool off on a hot summer day at Nehru Zoological Park in Hyderabad, India, Friday, May 29, 2015. Dizzying temperatures caused water shortages in thousands of Indian villages and killed hundreds more people over the past day, driving the death toll from a weeks long heat wave to more than 1,000, officials said Friday. (AP Photo/Mahesh Kumar A.)
Israelis and tourists relax on the beach in Tel Aviv, Israel, Wednesday, May 27, 2015. Israel is experiencing a heat wave with temperatures reaching about 42 degrees Celsius (107.6 degrees Fahrenheit) in Tel Aviv. (AP Photo/Oded Balilty)
An Indian passenger takes a bath beside rail tracks on a hot summer day at a railway station in Jammu, India, Monday, May 25, 2015. Severe heat wave conditions continue to prevail at several places in northern India with temperatures reaching 48 degrees Celsius (118 degrees Fahrenheit). (AP Photo/Channi Anand)
A boy plays by a fountain in Seoul on May 26, 2015 as temperatures soared to a high of 34 centigrade across South Korea. The Korea Meteorological Administration issued on May 25 this year's first heat wave advisory as it expects temperatures to exceed 33 degrees for the next few days. AFP PHOTO / JUNG YEON-JE (Photo credit should read JUNG YEON-JE/AFP/Getty Images)
Pakistani children cool off in a polluted canal in Islamabad, Pakistan, where temperature rose on Friday, May 29, 2015. Many cities in Pakistan are facing heat wave conditions with temperatures reaching 46 degrees Celsius (114.8 Fahrenheit) in some places. (AP Photo/B.K. Bangash)
A man drinks water from a bottle as he quenches thirst to beat the scorching heat in Mumbai, India, Friday, May 29, 2015. Dizzying temperatures caused water shortages in thousands of Indian villages and killed hundreds more people over the past day, driving the death toll from a weeks long heat wave to more than 1,000, officials said Friday. (AP Photo/Rajanish Kakade)
Indians play in a water pool at Jalavihar water park on a hot summer day in Hyderabad, India, Tuesday, May 19, 2015. Heat wave continued in many parts of northern Indian even as capital Delhi witnessed season's first severe storm on Tuesday bringing temporary relief from the heat, according to local reports. (AP Photo/Mahesh Kumar A.)
People sunbathe in a public park in Barcelona, Spain, Friday, May 15, 2015. The Iberian Peninsula has experienced record high temperatures for May as thermometers shot up to levels normally only seen in midsummer. (AP Photo/Emilio Morenatti)
An Indian commuter cools off by bathing in the water from a supply pipe by the tracks at a railway station in Allahabad, India, Sunday, May 3, 2015. (AP Photo/Rajesh Kumar Singh)
A white tiger swims in a pool at Nehru Zoological Park in the Indian city of Hyderabad on May 29, 2015. Hospitals in India battled May 28, 2015, to treat victims of a blistering heatwave that has claimed more than 1,700 lives in just over a week -- the highest number recorded in two decades. Hundreds of mainly poor people die at the height of summer every year in India, but this year's figures are already the highest since 1995, when official data shows 1,677 people succumbed to the heat. AFPHOTO/ Noah SEELAM (Photo credit should read NOAH SEELAM/AFP/Getty Images)
Indian horseman Rahul and his horses cool off in a canal on the outskirts of Jalandhar on May 28, 2015, as scorching weather conditions continue across India. More than 1,100 people have died in a blistering heatwave sweeping India, authorities said, as forecasters warned searing temperatures would continue. AFP PHOTO/SHAMMI MEHRA (Photo credit should read SHAMMI MEHRA/AFP/Getty Images)
A mirage shimmers over Rajpath leading to India Gate in New Delhi on May 28, 2015. More than 1,100 people have died in a blistering heatwave sweeping India, authorities said, as forecasters warned searing temperatures would continue. AFP PHOTO / Chandan KHANNA (Photo credit should read Chandan Khanna/AFP/Getty Images)
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Eastern Canada and parts of the Great Lakes and New England were the few locations much colder than average so far in 2015, according to NOAA. Parts of the north Atlantic Ocean, eastern Atlantic Ocean off west Africa, and Southern Ocean near the tip of South America were also somewhat cooler than average in the year's first six months. Interestingly, a small area of the north Atlantic Ocean southeast of southern Greenland was record cold in January-June 2015.
El Nino doesn't guarantee that happening, but it's worth pointing out the previous two record warm years in NASA's dataset prior to last year, 2010 and 2005, both featured El Ninos that ended early in the year, rather than persisting through an entire year.
January, February, March and June 2015 were each warmer than 2014. April was roughly comparable, but May was slightly cooler than May 2014, NASA's analysis found.
June 2015 eclipsed 1998 as the warmest June in the NASA GISTEMP analysis, which merges data from conventional land-based stations and reconstructed sea-surface temperature data from NOAA and dates to 1880.
NASA's analysis found the most pronounced warm anomalies in June 2015 were over the a strip from northern Russia south to the Arabian peninsula and from the Arctic Ocean north of North America southward into the northeast Pacific Ocean, the western United States and western Canada. Pockets of notable June warmth were also seen in central Africa, southwest Europe, central South America, off South America's northwest coast and northeast Australia.
The NOAA analysis found that Earth set a record warm June for the second year in a row.
Australia chalked up its fifth warmest June in 106 years, Austria tallied its tenth warmest June in 249 years of records, and Spain sweated through its sixth warmest June dating to 1961, according to NOAA.
Conversely, NOAA said a late June cold outbreak in New Zealand lead to the coldest temperatures, there, in 20 years, including a teeth-chattering June 24th low of -21 degrees Celsius (-5.8 degrees Fahrenheit) at Tara Hills.
February, March, May and June have set their respective warm records so far in 2015, according to NOAA. NASA's analysis found no month in 2015, so far, has ranked lower than its third warmest respective month. Four of the first six months -- January (tie), March, May and June -- were the warmest respective month on record in the JMA analysis.
Going back to the start of 2014, NOAA found 10 of the 18 months set or tied their respective month's global warmth record, at the time.
Ultimately, the important takeaway is not whether one particular month or year is a fraction of a degree warmer or cooler than another, but the long-term trend.
Nine of the 10 warmest years in NASA's 134-year database have occurred this century, with the exception of 1998, which featured the tail end of one of the strongest El Ninos on record.
The last year in NASA's dataset globally cooler than average was 1976.
The last cooler-than-average month in NASA's dataset was September 1992, more than 22 years ago. In the 462 months from January 1977 through June 2015, only seven months have been cooler than average, according to NASA.