It is a pure coincidence. Nothing special.
The point at which the Celsius and Fahrenheit scales meet is -40 degrees. -40 degrees Celsius is equal to -40 x 9 = -360 / 5 = -72 + 32 = -40 degrees Fahrenheit.
The scales of degrees Celsius and Fahrenheit are equivalent at -40 degrees.
-40 degrees is the temperature at which the Fahrenheit and Celsius scales coincide.
Was that on purpose? Because it just so happens that -40 is where the two meet! -40 degrees Celsius = -40 degrees Fahrenheit. Was that on purpose? Because it just so happens that -40 is where the two meet! -40 degrees Celsius = -40 degrees Fahrenheit.
The temperature when both the Celsius and Fahrenheit scales are the same is - 40 degrees.
-40 degrees is the same in Fahrenheit and Celsius.
The scales of temperature cannot all meet, as the Kelvin and Celsius scales have the same size degrees but different zero points. Absolute Zero is 0° Kelvin, and equal to -273.15 °C or -459.67 °F. Because the Celsius and Fahrenheit scales are offset by 32° at their starting points (freezing point of water), the two scales do have a common numerical point at -40° (minus 40 degrees). (see related question)
The temperature where Celsius and Fahrenheit are the same is -40 degrees.
The temperature at which Celsius and Fahrenheit scales are equivalent is -40 degrees.
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The temperature reading that is the same on both Celsius and Fahrenheit scales is -40 degrees.
At -40 degrees on both scales.