Step 1: Use the trigonometric identity.
We know that:
\[
\sin \theta = \cos(90^\circ - \theta)
\]
Thus:
\[
\sin 31^\circ = \cos(90^\circ - 31^\circ) = \cos 59^\circ
\]
Step 2: Substitute this into the given expression.
So,
\[
\frac{\sin 31^\circ}{\cos 59^\circ} = \frac{\cos 59^\circ}{\cos 59^\circ} = 1
\]
Step 3: Conclusion.
Therefore, the value of $\frac{\sin 31^\circ}{\cos 59^\circ}$ is $1$.