Global Climate Report - Annual 2017
Monthly temperature anomalies versus El Niño

« Global Climate Report - Annual 2017


Monthly temperature anomalies versus El Niño


The graphic below depicts the monthly global temperature anomalies—that is, each month compared its 20th average—since 1980, and the influence of the El Niño - Southern Oscillation (ENSO) phenomenon.

The height of the bar represents the global temperature anomaly for the month. The color of the bar represents the ENSO condition, as represented by the temperature anomaly in the Niño3.4 region during that month. Months colored in red had Niño3.4 temperatures more than 0.5°C (0.9°F) above the 1981-2010 "normal". This is analogous to an El Niño condition. Blue represents La Niña-like conditions, more than 0.5°C (0.9°F) cooler than normal. The official ENSO status designation from NOAA's Climate Prediction Center is more sophisticated, and assesses ENSO conditions over multiple months. However, the single-month approach here is useful to see ENSO's impact on global temperature anomalies.

Several factors are apparent in the figure. First, nearly every month since 1980 has been above the 20th century average, and has generally warmed through the period. Second, El Niño-like conditions (those months in red) tend to be warmer than neighboring periods, and La Niña-like conditions (blue) tend to be cooler. Third, protracted El Niño-like episodes tend to warm through the event, while La Niña-like episodes tend to cool through the event. Fourth, and finally, there are exceptions to all of the above points.

  • The months of January through April 2017 rank among the 15 warmest monthly global land and ocean temperature departures on record (1,656 monthly records).
    • January 2017 tied with June 2016 as the 11th highest monthly temperature on record.
    • February 2017 ranked as the eight highest monthly temperature on record.
    • March 2017 ranked as the sixth highest monthly temperature on record.
    • April 2017 tied with February 2015 as the 15th highest monthly temperature on record.
  • March 2017 marks the first time since April 2016 that the global land and ocean temperature departure from average is greater than 1.0°C (1.8°F).
  • March 2017 is also the first time a monthly temperature departure from average surpasses 1.0°C (1.8°F) in the absence of an El Niño episode in the tropical Pacific Ocean.

Monthly global temperature anomalies since Jan 1980, with Nino3.4 conditions shown
Global monthly temperature anomalies, with Niño3.4 conditions