Canada

I always did find it silly that it wasn't at least the same as parks where lower speed is required dawn till dusk.

Like, even on the weekends and after school, schools have parks and playgrounds where the children go to play. They don't just appear at 730am and disappear at 5. These signs just add a later of confusion. Like, if it's a pro-d day is it technically a school day? Do the parent who know school is out get to drive faster than those who don't have children and dont know it's not a school day?

Or should the signs read weekdays instead?

It's kind of silly.

It is very dependent on the community and the school, but there’s plenty of schools that are absolutely deserted outside of school hours for a variety of reasons. Some schools have playgrounds or basketball hoops or the like but some don’t, or they’re locked up, so why would kids go that way instead of the park.

The risk has been identified as high population of children during certain hours crossing streets etc., and is mitigated by lowering speed limits during those hours. Whether it’s an accurate risk assessment is a good question though. Personally, I think the influx of drop-off traffic is worth mentioning, but who am I to say?