Weather and Climate

It’s Likely Earth’s Six Warmest Years on Record Are the Last Six Years

Last week the National Oceanic and Atmospheric Administration (NOAA) announced that July 2019 was the Earth’s hottest month since record keeping began in 1880, besting July of 2016. Meanwhile the Japanese Meteorological Agency declared July 2019 to be tied with July 2016 as the hottest on record and NASA determined last month to be tied with August 2016 as the hottest on record. While gauging the temperature across much of the Earth’s land and oceans is uniform, each agency differs in how it collects information in areas with few surface weather stations, like the Arctic. The resulting discrepancies in ranking are somewhat meaningless, though, since the conclusions are nearly identical.  

It’s not just July that was hot, though. So far this year (January through July) is tied with 2017 as the warmest on record – behind, you guessed it, 2016. Based on NOAA’s general global forecasts for the rest of the year, 2019 will almost certainly be ranked in the top 5 warmest years on record. If that pans out then the Earth’s six warmest years since record keeping began in 1880 will be 2014, 2015, 2016, 2017, 2018, and 2019.

As Wunderground’s Dr. Jeff Masters points out, July’s record heat is particularly interesting because it occurred during the minimum of the weakest solar cycle in over 100 years. It’s also remarkable considering that a strong El Niño event (warmer-than-usual ocean temperatures in the Equatorial Pacific) was not present during the month – record warmth is usually recorded during strong El Niño events and when a solar cycle is at its maximum.

As usual, it’s important to put local conditions in a global context. July 2019 was the hottest on record for the Earth, but as the map above shows, much of the U.S. and Canada experienced normal to slightly above normal temperatures. It’s reminiscent of the late days of 2017 and early days of 2018 when the “Bomb Cyclone” brought bitterly cold temperatures to the U.S East Coast, including Georgia. While that led many to theatrically express doubt over climate change, 2017 and 2018 ended up being Georgia’s warmest year and 9th warmest year on record, respectively (the U.S.’s 3rd warmest and 14th warmest, respectively). Spoiler: 2019 is rapidly approaching 2017’s title.

As of the date of publishing, August 2019 is currently the third warmest August on record in Atlanta. Meanwhile, temperatures in the city up to this point in the year currently rank as the third warmest since record keeping began at Atlanta’s Hartsfield-Jackson International Airport in 1930. Only 2012 and 2017 have had warmer temperatures up to this point in the year. Seven of the 10 warmest years on record in Atlanta have occurred since 2000 while all 10 have occurred since 1990. It should be no surprise then that this decade, so far, is the warmest on record for the city, running close to 1°F above the next warmest decade, the 1990’s. See our Weather + Climate page for real-time charts showing this data.

It’s apparent from the graph below of the average temperature* deviation from normal for each month this decade that far more months have seen above-normal temperatures than below-normal temperatures. Only 26% of months since January 2010 have recorded below-normal average temperatures in Atlanta. Note that NOAA uses the temperatures collected between 1981 and 2010 to define “normal.”

The average temperature in August in Atlanta is currently running about 4°F above normal. If this holds, as forecasts predict, we would extend our streak of months with above-normal average temperatures to 16. You have to go back to April of 2018 to find the last month that recorded below-normal average temperatures. That 15-month period is the longest streak this decade, beating the 9-month period that occurred during 2016. The longest streak of months with below-normal temperatures is three, which occurred between January and March 2010 and November 2010 and January 2011. *Update 9/29/19 – August finished 3.1°F above normal and September will finish almost 8.5°F above normal in Atlanta.

We’ll have see how the rest of the year goes. You can keep track of the changing monthly and yearly temperature rankings in Atlanta by looking at our charts on the home page and on our Weather + Climate page. Or you can go right to the source by looking at NOAA’s National Center for Environmental Information ranking tool that you can use for every state and for many cities throughout the country.

*the average temperature is simply the high temperature for the day plus the low temperature for the day, divided by two. Those daily averages then get averaged themselves to find the monthly average temperature.

Cover Photo by Brett Weinstein via Flickr

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