SST (L2)

More detail

The picture is one to two hours old.

Step back an hour or two and take the hour that was clearest over your spot. Each picture covers a whole hour, so the current hour is never on the map. The layer covers the Gulf of America, the East Coast and Baja.

It reads the skin of the water, the very top, so the afternoon warm-up shows more strongly here than on any other temperature layer, and on a calm sunny afternoon it runs warm against your gauge, which reads about three feet down.

How it relates to the other temperature layers. Use this layer when the extra hour matters and SST (L3 Composite) for a cleaner picture. SST (2hr Composite) is the freshest temperature in the app, rebuilt about every five minutes. SST (MUR 1 km) is a daily map with the cloud holes filled in by estimate. SST (ACSPO 2km) is a daily nighttime map that leaves cloud blank. Sea Surface Temperature, from HYCOM (U.S. Navy model), is a forecast, not a measurement. All of them share one color scale. For breaks drawn as lines, use SST (GOES-19) Fronts. For temperature below the surface, use Water Temperature at Depth.

If the colors look wrong after you change settings, reset the range in Layer Settings. The default is 41.9 °F to 91.4 °F.

The numbers

How often it updates	Every hour, 24 frames a day
How fresh it usually is	1 to 2 hours
How detailed it is	The satellite's own sample over the Gulf is about 1.5 nautical miles
Where it covers	Gulf of America, East Coast and Baja
How far back you can look	8 days back, hour by hour
Goes blank under cloud?	Yes, on purpose
Observed or modeled	Observed. Nothing is filled in
What you see on screen	Fahrenheit by default, Celsius if you switch. Skin temperature, the very top of the water

Source: a satellite picture from the GOES-19 satellite (NOAA).