Here's how to convert temperatures.
To go from F to C...
Subtract 30 and divide by two.
So 100F goes down to 70, and halved to get 35C (which is about what we've got at the moment!)
To go from C to F...
Double it and add thirty.
So, 25 C gets doubles to 50, then add 30 and you get 80F.
It isn't exact, but it's reasonably close, certainly close enough to know if it is going to be hot or cold or whatever.