Apparently, if you keep a tree frog in a jar half full of water and provide it with a little ladder to climb, it will predict good weather by climbing the ladder, and wet weather by retreating back down into the water. I know that tree frogs do climb trees in good weather and create an infernal din croak charmingly for hours on end, so I guess there's at least some truth in the frog ladder.
One cold winter morning a California friend came to visit me. I looked out the window and asked "how is it out there? It looks cold." She thought I was joking because it is preposterous to say that it looks cold. It took me a while to be able to articulate what "looked"cold. The rhododendrons are an obvious one, their leaves roll up and hang down when it's really cold. Also the grass has a crispy sort of look. Of course ice in the birdbath is a clue!
I can tell when the pressure drops and a storm is on the way because I can feel it in my foot, in the place where I had a fracture years ago.
They say you can tell the kind of winter it's going to be by the thickness of the woolly bear caterpillars. They always seem of relatively uniform thickness to me.
I was told that the length of the center (brown) band on a wooly bear caterpillar was the indicator for the length of winter. So the longer the band the longer the winter. I must see a few hundred of those things every year and I can't discern any sort of consensus among them. I got long ones, short ones and even some with no bands at all.