The NOAA Coral Reef Watch (CRW) daily global 5km Sea Surface Temperature (SST) Anomaly product presented here is based on Coral Reef Watch's CoralTemp v3.1 and daily climatologies with the reference (baseline) time period of 1991-2020, following the standard 30-year reference period used by meterorologists and climate scientists to define "normal" weather conditions. CoralTemp v3.1 is a satellite nighttime SST data set, spanning January 1, 1985 to the present and updated in near real-time.

The data and images provided here are for 2006-present only, as the 1991-2020 baseline period has been used for calculating SST Anomalies of 2006-present according to the guidance on defining climatology for calculating SST anomaly.

Note that this SST Anomaly product is provided in parallel to the SST Anomaly product of Coral Reef Watch's daily global 5km Coral Bleaching Heat Stress Monitoring Product Suite that is based on climatologies with a specific reference (baseline) of 1985-1990 plus 1993 for its designed applications.

Climatology: CoralTemp v3.1 SST values from January 1, 1991 to December 31, 2000 were used to derive the daily climatologies. The daily climatology value for each calender day of year (other than the 29th of February) is the average daily SST value calculated among the 30 values of the day from the 30 years (1991-2020). If ice was present at a data grid on any of those 30 days, the climatolgy was not calculated for that day at that data grid and an ice flag was assigned. This leads to dark-grey no-data grids in high-latitudes shown in daily SST Anomaly images and flagged miss-data grids in netCDF data files. The daily climatology for February 29 was derived by averaging the climatology values for February 28 and March 1.

No-data grids: Most, if not all, of the no-data grids are in high latitude regions with no corresponding daily climatology value avaiable due to the presence of ice during the baseline time period. See the climatology section above for details.