A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hello !
You'll need to use a custom number format : type your temperature in the cells, select those cells, press Ctrl +1 to open the "Format cells" window.
Go to Number > Custom, and in "Type", enter 0"°C"
Click "OK".
This way, Excel will always display the Celsius sign next to your tempature, but without altering the data (it's still a number).
Please let me know if you have any other question !