How to write degree celsius(°C) symbol in LaTeX?

You are all familiar with the degree Celsius (°C) symbol, which is formed by placing (°) next to the letter C.

In LaTeX, there is no predefined command for the Celsius (°C) symbol. However, you can create it by combining C with (°). For example:

\documentclass{article}
\begin{document} 
  \[ ^\circ C \]
  \[ {25}^\circ C \]
\end{document}

Output :

Using textcomp and mathcomp Packages for °C

The textcomp and mathcomp packages offer predefined commands \textcelsius and \tccentigrad for the Celsius symbol.

Alternatively, in textcomp, you can create it by combining C with \textdegree.

\documentclass{article}
\usepackage{textcomp,mathcomp}
\begin{document} 
  51 $\tccentigrade$
  25 \textdegree C \\
  49 \textcelsius
\end{document}

Output :

The syntax for this \SI command is slightly different, and temperature values and \celsius or \degreeCelsius commands are used as arguments.

\documentclass{article}
\usepackage{siunitx}
\begin{document} 
 \[ \SI{49}{\celsius} \]
 \[ \SI{25}{\degreeCelsius} \]
\end{document}

Output :