For day–date problems:
\begin{itemize}
\item First check whether the year is a leap year,
\item Use the odd-days method systematically,
\item Always verify month-wise day counts.
\end{itemize}
Step 1: The year 1979 is not a leap year.
Step 2: Using the calendar or odd-days method, we calculate the total number of odd days up to 13 February 1979.
Step 3: After accounting for the days of years and months preceding 13 February 1979, the resulting day corresponds to Wednesday.
Step 4: Hence, 13 February 1979 was a Wednesday.