This frosty world.

A Blipper asked me the other day why the hoar frost forms round the edges of the leaves before it affects the central area.
I admit that I did not know the answer.
But I made a guess. The edges of the leaves are thinner and colder than te middle part and any moisture there would be quicker to turn into ice.

Does anyone have a better idea ?

My extra shows that if you get caught in a snow shower you can avoid it by standing under a tree.