what "aberration of nature" frightens scout?

The aberration she speaks of is cold weather and snowfall.

We had two weeks of the coldest weather since 1885, Atticus said. Mr. Avery said it was written on the Rosetta Stone that when children disobeyed their parents, smoked cigarettes and made war on each other, the seasons would change: Jem and I were burdened with the guilt of contributing to the aberrations of nature, thereby causing unhappiness to our neighbors and discomfort to ourselves.