A useful habit (which I think I picked up while studying physics at sixth-form) is to describe temperature intervals in “Celsius degrees” (and specific temperatures in “degrees Celsius”).
So a temperature of 43 degrees Celsius is 18 Celsius degrees hotter than 25 degrees Celsius.
32 Fahrenheit degrees are equivalent to 18 Celsius degrees; but 32 degrees Fahrenheit is equivalent to 0 degrees Celsius.
(There's no real need to do this when using absolute units, but I'd still pluralise the interval and not the absolute value: 316 kelvin is 25 kelvins hotter than 291 kelvin.)
So a temperature of 43 degrees Celsius is 18 Celsius degrees hotter than 25 degrees Celsius.
32 Fahrenheit degrees are equivalent to 18 Celsius degrees; but 32 degrees Fahrenheit is equivalent to 0 degrees Celsius.
(There's no real need to do this when using absolute units, but I'd still pluralise the interval and not the absolute value: 316 kelvin is 25 kelvins hotter than 291 kelvin.)