As part of their series of graphs of global average temperatures, NOAA produces this one below which shows the temperature anomalies by ENSO phase. As expected the graph shows that El Niño year (in red) tend to be the warmest because of the large expanse of above-normal sea surface temperatures across the eastern Pacific Ocean that are associated with El Niño, while La Niña years (in blue) tend to be colder than normal.  What is surprising this year is how warm it is across the globe even with no El Niño present.  In fact, the global temperatures this year are warmer than any previous El Niño year prior to the episode that just ended. This warmth is most likely contributing to the string of tropical systems that are now moving across the Eastern Pacific Ocean off the coast of Mexico and may contribute later in the Atlantic tropical season to an active year there, as well.

Global monthly temperature departures (from 1981–2010 average) color-coded by whether the Pacific was experiencing an El Niño (red), a La Niña (blue) or neutral conditions (gray). CREDIT: NOAA