GRAND RAPIDS, Mich. (WOOD) — In honor of National Superhero Day I decided to answer a pretty common Ask Ellen question with a fun superhero answer.

Viewers usually want to know what the difference is between partly sunny and partly cloudy. Both terms can be used when roughly half the sky is covered with clouds. According to the national weather service, either is appropriate when the sky is three-eighths to five-eighths covered.

So why are there two terms for the same sky? The difference has to do with the time of day! Think of it like Bat Man. During the day, he’s Bruce Wayne. At night, he is Batman. 

The same is true of the word “partly.” During the day, the sky is partly sunny. During the night, we use partly cloudy. 

Mostly sunny means there is more sun than clouds. Mostly cloudy means there is more clouds than sun. Overcast means the sky is completely covered in clouds.