@khird interesting theory. Why only on certain days, though?

@mjambon I'd guess it's because it's not very useful to quote a number when you can see "to the nearest cloud", so Yahoo only reports it on a clear day.

Another possibility might be humidity, but I wouldn't know why it's only sometimes shown in that case.

@khird unfortunately, it's also common on cloudy and rainy days. 🤔🤔🤔