Pacific Climate Update
Coral Bleaching Heat Stress Analysis and
Seasonal Guidance through June 2020

(Released March 3, 2020)

Current conditions:

NOAA Coral Reef Watch's (CRW) near real-time satellite monitoring shows the sea surface temperature (SST) as alternating between below- and above-average along the equator in the eastern and central equatorial Pacific; as being below-average in the southeast and northeast Pacific; and as being above-average throughout the remainder of the ocean basin (Figure 1). El Niño Southern Oscillation (ENSO)-neutral conditions remain. Over recent months, warm anomalies (>1°C) have surrounded Tuvalu, the Solomon Islands, and the Great Barrier Reef (GBR), Australia. ENSO-neutral is expected to continue through Northern Hemisphere spring (60% chance) and into summer 2020 (50% chance).

2020 Mar 03 SST Anomaly map
Figure 1. NOAA Coral Reef Watch's Satellite Sea Surface Temperature Anomaly product for the Pacific region.


Currently, the highest HotSpots (≥1°C) are concentrated around Vanuatu, New Caledonia, and the GBR (Figure 2). Bleaching Alert Level 2 conditions (associated with severe, widespread bleaching and significant coral mortality) ramped up over much of the southern portion of the GBR in February and are expected to reach a peak this month (Figure 3). This mass bleaching event on the GBR will be the third of its kind in just five years, and is predicted to be the most widespread ever.

2020 Mar 03 HotSpots map
Figure 2. NOAA Coral Reef Watch's Satellite Coral Bleaching HotSpot product for the Pacific region.
2020 Mar 03 7-day Maximum Composite Bleaching Alert Area map
Figure 3. NOAA Coral Reef Watch's Satellite Bleaching Alert Area (7-day maximum) product for the Pacific region.

CRW's most recent Four-Month Coral Bleaching Outlook (Figure 4) projects heat stress (Bleaching Alert Level 2) will continue on the GBR until early April, then dissipate and expand northward and eastward (at Alert Level 1) toward Tuvalu, American Samoa, and French Polynesia in May. By June 2020, the majority of the heat stress will be near the equator and western equatorial Pacific.

2020 Mar 03 Four-Month Bleaching Outlook map
Figure 4. NOAA Coral Reef Watch's Four-Month Coral Bleaching Heat Stress Outlook of March 3, 2020 for the period March-June 2020 for the Pacific region.

***NOTE: This report incorporates NOAA Coral Reef Watch's Version 3.1 (or v3.1) daily global 5km satellite-based coral bleaching heat stress products and v5 Four-Month Coral Bleaching Heat Stress Outlook.***

To monitor the intensity and location of bleaching heat stress in your coral reef region of interest, please follow NOAA Coral Reef Watch's satellite monitoring and outlooks closely in the coming weeks: and


CRW's current satellite and modeled products can be found at:

CRW's Four-Month Coral Bleaching Heat Stress Outlooks can be found at:

CRW's 5km satellite Regional Virtual Stations can be found at:

Sign up for automated bleaching alert emails for CRW's 5km Regional Virtual Stations at:

Please report bleaching events (or non-events) at:

For more information, please contact


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