The slope of the scales has no bearing on whether percentages are meaningful here. The problem with both systems when it comes to percentages is that neither sy

The slope of the scales has no bearing on whether percentages are meaningful here. The problem with both systems when it comes to percentages is that neither system has 0 set to a natural 0. This leads to an entirely arbitrary point on the scale where decreases in the unit will approach a 100% difference and then suddenly start decreasing again. If anything Fahrenheit should be less insane because at least the artificial 0 is likely to stay much further away in the data they're quantifying so the percentages stay reasonable.