**Most power transformers will operate at 100 degrees C quite safely,
though I prefer to see less than 75 C. I have no idea what 125 degrees F is
and I have no interest either, but I suspect it is less than 75 C.

It's such a big deal to convert, isn't it?

Start by subtracting 32. That's 93, which you can round off to 90. Then take
5/9 of that -- 50, which is close enough. You can do it in your head in a few
seconds.

There's no need to memorize the formula, if you remember that 0 and 32 degrees
are the same point, and 1 degree F is 9/5 degree C.


[ASIDE] This is an international group. Almost none of the planet's
population (less than 5%) bothers with archane measurements,
like degrees F, anymore. Please learn the Metric system.

First, it's spelled arcane (hidden, mysterious). Which isn't the word you
want -- you want archaic.

Metric is not capitalized.