People who fish and dive love it when the winds are light and the seas are calm.
Coral reefs, not so much.
That's because calm seas means sunlight can penetrate better and heat up the water. When sea temperatures pass a 30.4 degrees Celsius average for a month — that's 86.72 degrees Fahrenheit — corals start to bleach.
The corals expel the zooxanthellae, or symbiotic algae that gives them their colors.