There is more than one place on Earth where the temperature can potentially be the same in Fahrenheit and Celsius. There is only one temperature that is the same in both Fahrenheit and Celsius, but that temperature can occur at more than one spot on Earth’s surface.
The Fahrenheit and Celsius scales only match up at one temperature. Each degree Celsius is equal to 1.8 degrees Fahrenheit so the two scales do not match at most points. However, -40 degrees Celsius is the same temperature as -40 Fahrenheit. We can see this because the formula to convert from Fahrenheit to Celsius is
Degrees Celsius = (1.8 x Degrees Fahrenheit) + 32.
Now, let us plug in -40 as the temperature in Fahrenheit. We would get
Degrees Celsius = (1.8 x -40) + 32 which becomes -72 + 32 which is -40.
So, when the temperature is -40 Fahrenheit, it is also -40 Celsius.
But there are many places on Earth that have had temperatures that low. As can be seen in this link, temperatures lower than that have been recorded in Antarctica, Asia, North America, and Europe. This means that at some point, the temperature must have been -40 degrees on all of those continents.
Thus, there is more than one place on Earth where it is possible to have the temperature be the same in Fahrenheit and Celsius.