I'm not sure you fully read my comment. It only works for 2018. If you did their analysis any other year, you'll get the 1st percentile is -4°F or something similar.

I only called out the "nearly exactly" part of the claim. US weather is approximately in the range of 0-100°F, give or take 20 degrees. But the analysis found 0°F to be nearly exactly the first percentile of daily highs and lows, to within a twentieth of a percentile point.

It's true that US temperature is around 0°F-100°F but usually false that those temperatures are the 1st and 99th percentile.