Coral, NOAA Reef Watch, DHW

NOAA Coral Reef Watch publishes a daily Degree Heating Week, DHW, for a virtual regional Puerto Rico station. The DHW accumulates coral-bleaching HotSpot values above one degree Celsius across twelve rolling weeks, in degree-Celsius-weeks. The product page and the ASCII time series were alive at capture. This essay is a snapshot, not a live gauge and not a copy of a Florida Keys board.

Captured August 22, 2026. Last time-series row at capture: August 20, 2026. The product did not give a dead link.

On August 20, 2026 the Puerto Rico regional file listed the ninetieth-percentile HotSpot DHW above one as 0.0. HotSpot values that day were positive but below the one-degree threshold that accrues DHW, about 0.83 in the station's ninetieth-percentile column. Sea surface temperatures were high for the calendar, in the high twenties Celsius, without yet stacking a bleaching-week total in that regional statistic. A zero is a number. It is not the claim that no reef pixel was stressed.

The regional DHW is a ninetieth-percentile construct within a station polygon, designed so that a few hot pixels do not speak for every reef from Mona to Culebra. Single-pixel experimental stations exist for individual Puerto Rico reefs; this snapshot uses the regional file the gauges page links to. If a later reader finds a different DHW on a later day, that is the point of a dated snapshot. We do not pretend to be a nowcast.

Hurricanes cool and mix the surface and can also break coral mechanically. María and Fiona are storm records. They are not a substitute for a heat product. Bleaching in a quiet, hot late summer is a mortality path distinct from a Category Four at Yabucoa. This site keeps those paths in separate essays on purpose.

The DHW scale in the global product runs from zero toward twenty. The alert levels on the station pages were still on a legacy numbering at capture; we print the base DHW, not a copied board chip.

Cite the text file, cite the date, print 0.0 degree-Celsius-weeks for August 20, 2026, and leave the Keys out. The coral here is a heat ledger adjacent to the island, filed under landfall because storms and heat share the same coast, not because this page is a bleaching video wall.

Sources: NOAA Coral Reef Watch, serie de tiempo de la estación virtual regional de 5 km de Puerto Rico; NOAA Coral Reef Watch, gauges de Puerto Rico. Freeze 2026-08-22.