Today and yesterday there have been a large amount of questions on Arqade (not Meta) that have been downvoted, put On Hold, etc. Does this happen often when schools [in general] let out for summer?
Not really? I mean, there may be some correlation between peoples' increased free time and their tendency to ask more questions based on what they play in their free time, but there doesn't seem to be a particularly large increase in on-hold/low-quality that can't be explained by more questions in general.
Lacking any concrete stats, I'd say the percent of low quality questions likely remains relatively constant, but the frequency increases as the frequency of questions in general increases.