These thermometers only measure the temperature in five-degree increments, and the lowest measurement this particular model will show is 50 degrees. It works for me because anything below 50 is cold, isn't it? And the details don't much matter.
50 is when I'll send the kids outside to play without bundling; the degree at which I'll toss them out the backdoor and not worry about their welfare. This picture is from last last week, as we spent the early part of a Sunday morning watching for that first bubble to drop and tell us the neighborhood has left the cold 40s behind.
The weekend before that it was almost 80 here, and now as I type it's snowing outside our windows. I think March is off her meds.