This is the exact same way you would normally find the darkest parts of the image when you're removing any color casts from the shadow areas, but now, thanks to the Difference blend mode, these darkest areas represent the areas closest to midtone gray.
The warmest sea in Key Largo in March is 26Â°C/79Â°F, and the coldest sea temperature in March is 22Â°C/72Â°F. Average water temperature in Key Largo in March is 24Â°C/75Â°F. You can choose any other years:
Monthly Key Largo water temperature chart. The bar chart below shows the average monthly sea temperatures at Key Largo over the year. Monthly average max / min water temperatures. The graph below shows the range of monthly water temperatures over several years.