This year's El Niño could become most extreme on record

Ocean temperatures are already hotter than normal for this time of year in the Central Equatorial Pacific compared to even the hottest El Niños on record.

Relative Oceanic Niño Index

Note: Temperatures reflected are within the Central Pacific El Niño region: 170°W to 120°W and 5°S to 5°N and update monthly.

Source: NOAA

Graphic: Sam Hart, CNN