Because most of Apple's designers do not have the discipline or the blessedly smaller scope to consistently output well designed interfaces anymore, and are riding the momentum of those that came before and the current of hot air of their own supply these days.
The idea that Apple is full of good designers should be forgotten. They're as mid and sloppy as any other large tech company.
In Carrot and Apple Weather, I think the daily temperature graphs should be chronological so for those days where the low is late at night (temperature drops all day) you know when the cold is happening at a glance.
In all other places in the app, the low is to the left of high.