Our global temperature continued its upward trend last month. May 2018 marked not only the fourth warmest May on record, but also closed out the planet’s fourth warmest March to May season, known as meteorological spring in the northern hemisphere.

According to the State of the Climate report by NOAA’s National Centers for Environmental Information, Earth’s combined average temperature for May – over both land and sea surfaces – was 60.04°F, which is 1.44°F above the 20th-century average. The years 2014-2018 now rank among the five warmest Mays on record.

This May also marked the 401st consecutive month with a global temperature above its long-term norm. That means the last time any month posted a below average reading was December 1984.

While heat dominated most of the planet this May, some places were particularly warm, including much of Europe and North America. Here in the contiguous US, it was our warmest May ever recorded. The previous record had been in place since 1934.

Globally, the three-month period of March, April, and May was also unusually warm. NOAA reports that Earth’s average temperature for the season was 1.48°F above the 20th century average of 56.7°F. That makes it the fourth warmest such period on record.

These soaring temperatures are largely attributed to the long-term trend of human-caused climate change. ENSO-neutral conditions prevailed in May, which means there was neither an El Niño nor a La Niña in the Pacific to influence global weather patterns.

Year to date, the first five months of 2018 tied 2010 as the fourth warmest such period of any year on record. Global temperature records date back to 1880.

May 2018 was the fourth warmest May ever recorded on Earth. Credit: NOAA