The formula for converting Fahrenheit to Celsius is:

```

°C = (°F - 32) × 5/9

```

Plugging in 23 degrees Fahrenheit, we get:

```

°C = (23 - 32) × 5/9

```

```

°C = (-9) × 5/9

```

```

°C = -5

```

Therefore, 23 degrees Fahrenheit is equal to -5 degrees Celsius.