There are no X and Y values other than statistical averages of the small, measured portions of the entire planet. Even those numbers are then subjected to various “adjustments”.
Put one foot in a bucket of extremely hot water and the other in a bucket of ice. Theoretically, you’ll be quite comfortable since the average temperature is midway between the two.
I’m talking about satellite data. There IS an average surface temperature of the entire earth, and it has been going down for eighteen years.
But I can’t find the actual numbers.