Temperatures and Prime Numbers

Or if you thought for a minute before rushing to write code, you would reflect that any temperature that is a prime number in both Celsius and Fahrenheit must be an integer in both Celsius and Fahrenheit, and therefore must be a multiple of 5 in Celsius.

Unless you count -5 as prime (and you don't, or you would have noted that -5C = 23F is prime on both sides), there is only one prime number that is a multiple of 5...