**Notice to Users: NOAA/NESDIS plans to discontinue all operational 50km resolution satellite coral bleaching heat stress monitoring products. They are being replaced with higher resolution 5km satellite products. 50km products to be retired and replaced with 5km products are: sea surface temperature (SST), SST Anomaly, Coral Bleaching HotSpot, coral bleaching Degree Heating Week, Bleaching Alert Area, and the Virtual Stations.

Archived data and images will still be available at https://coralreefwatch.noaa.gov.

Research-supported 5km resolution versions of the products and images are available now at: https://coralreefwatch.noaa.gov/product/5km/index.php.

A 30-day comment period is now open for users to send objections or concerns about this product retirement. Send comments to John.Sapper@noaa.gov.**

50km Degree Heating Week (DHW)
clickable global map of degree heating weeks
DHWs in Mediterranean and Red Sea DHWs around India DHWs east of Japan DHWs around Hawaii DHWs around Central America DHWs West of Africa DHWs in Mediterranean and Red Sea DHWs around southern Africa DHWs in the southern Indian Ocean DHWs around Australia DHWs in the South Pacific DHWs west of South America DHWs east of Brazil DHWs around southern Africa
Click on the image to zoom in.

Current images: Global | E.Hem. | W.Hem. | Pacific | Caribbean | Coral Triangle


Data Formats Available

images Image Archives
Regional imagery and image archives from NOAA/NESDIS' Office of Satellite and Product Operations (OSPO).
Google Earth Google Earth
All of our satellite data products are available on Google Earth.
Virtual Stations 50km Virtual Stations
Imagery, graphs, ASCII data, and e-mail alerts for reef pixels around the world.
animations Animations
Data animations and downloadable animated GIF files from NOAA/NESDIS OSPO.


The NOAA Coral Reef Watch (CRW) twice-weekly global 50km satellite coral bleaching Degree Heating Week (DHW) product presented here shows accumulated heat stress, which can lead to coral bleaching and death. The scale goes from 0 to 16 °C-weeks. Spatial resolution is one-half degree precisely. The DHW product accumulates the instantaneous bleaching heat stress (measured by Coral Bleaching HotSpots) during the most recent 12-week period. It is directly related to the timing and intensity of coral bleaching. Significant coral bleaching usually occurs when the DHW value reaches 4 °C-weeks. By the time the DHW value reaches 8 °C-weeks, widespread bleaching is likely and significant mortality can be expected.


Additional description in the 50km products tutorial.
Technical details on the methodology page and in Liu et al. 2013.