I always understood the limit as being from midnight to dawn. Midnight should probably be understood as the lunar zenith rather than the clock time as well.
Lunar zenith isn’t midnight. It can happy at any time, including during the day.
Sounds like a nifty way to introduce gradeschoolers to astronomic concepts.
The person who makes this remark in Gremlins 2 is immediately violently sliced open in a comedic but also horrific way. Probably the best response.