The formula to convert Fahrenheit ($F$) to Celsius ($C$) is:

$C = \frac{5}{9} (F - 32)$

Now, let's substitute $F = 23$ into the formula:

$C = \frac{5}{9} (23 - 32) = \frac{5}{9} (-9)$

Simplifying:

$C = \frac{5 \times (-9)}{9} = \frac{-45}{9} = -5^\circ C$

So, $23^\circ F$ is equivalent to $-5^\circ C$.

Would you like more details, or have any questions?

Here are some related questions:

1. What is the Celsius temperature for 50°F?
2. How would you convert $100^\circ C$ to Fahrenheit?
3. What is the freezing point of water in both Celsius and Fahrenheit?
4. How does the Celsius and Fahrenheit scale differ mathematically?
5. Can you explain the derivation of the Fahrenheit to Celsius conversion formula?

Tip: Always subtract 32 from Fahrenheit first before applying the $\frac{5}{9}$ ratio.