What does mr. avery say that bad children cause? what's ironic about this, given jem and scout's reaction to the snow?

In To Kill a Mockingbird, Mr. Avery says that bad or disobedient children cause the season to change and thus bring bad weather. The irony in all of this is that Jem and Scout are curious and fearful of the snow respectively and feel guilty for bringing this "bad" thing on themselves and their community. If snow were a punishment caused by Jem and Scout being bad, the children likely would not be moral enough to feel guilty about causing it.

Jorge owns his restaurant

If you would like, sure.