snow day

(noun) any day when school is cancelled unexpectedly, but not necessarily because of snow.
other causes include but are not limited to:
ice (bad roads), low temperature (buses can't start), winds, power outages, no heat, lice epidemic (school closes for cleaning), sickness (so many students are out sick that it's not worth keeping the school open).

I got a snow day!
But it's 60 degrees outside.
Yeah, but the wind knocked the power out at school.