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.

Niño 3.4 Sea Surface Temperature Anomaly 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 weekly.

Source: NOAA

Graphic: Sam Hart, CNN