Equatorial Pacific heat content (0-300 m)

Indices

A monthly NOAA CPC index: the average temperature anomaly of the upper 300 m of the equatorial Pacific, for three boxes (130E-80W, 160E-80W, 180W-100W), against the 1981-2010 average. Series heat_content_130e_80w_anom, heat_content_160e_80w_anom, heat_content_180w_100w_anom (degC).

Limits. Monthly, published early in the following month. It is an average over large boxes and does not show where exactly the warm water is.

How to read it

Above 0 = more heat stored below the surface than normal. Values above about +1 C in the east (180W-100W) keep El Nino going; a fall back toward 0 or below usually announces the end of the event a few months later. August 2026: +3.2 C in the eastern box, a very high value.

Why it matters for Koh Samui

The surface (Nino 3.4) follows the sub-surface with a lag of 1-3 months, so this is an early signal of how long and how strong the El Nino will stay, and so how long Samui should expect El Nino-type dry conditions.

Sources

• cpc.ncep.noaa.gov
• cpc.ncep.noaa.gov

ENSO status now

ONI (NOAA CPC)

+1.80 °C, JJA 2026 (previous +1.39 °C)

RONI (NOAA CPC)

+1.36 °C, JJA 2026

Nino 3.4 weekly (NOAA CPC / OISST)

+3.0 °C anomaly, week of 16 Sep 2026 (SST 29.6 °C)