The formula to convert Fahrenheit to Celsius is:

°C = (°F - 32) / 1.8

Now we can convert -50 degrees Fahrenheit to Celsius:

°C = (-50 - 32) / 1.8

= -82 / 1.8

= -45.56 degrees Celsius

So, -50 degrees Fahrenheit is equal to -45.56 degrees Celsius.