30 Fahrenheit is just below the typical freezing temperature of water.
30 Celsius is just a few degrees below normal body temperature . . . nice for casual swimming.
Edgardo might also have been referring to 30 degrees latitude.
Certainly in Celsius, because this temperature in Fahrenheit is a low temperature
Edgardo likely referred to 30 degrees Celsius since this temperature is warm enough for swimming. In contrast, 30 degrees Fahrenheit is below freezing, making it unsuitable for swimming. Thus, Celsius is the more logical choice in this context.
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