Re: Change from celsius to fahrenheit on a Nokia 635 phone
Go to Settings > region.
There are two fields there that are selectable... Country/Region which is where you are currently, I presume. The other is Regional Format and the default is "match phone language." I assume that is what your says.
Under that is an example of "Date, Time and Currency." It also shows what units display. I assume they match up with where you are.
If you change Region Format to English (United States) you will see Fahrenheit, dollars, miles, etc. It changes every unit display label.
I do not know of a way to change only the temperature label across the device...
That said; If you are talking just about one App that you use for weather, check that App's settings.
If you have more questions, need more help then join the site so you can reply in this thread.