The site you posted is slow to open so I quit waiting. Guessing that you are looking at the weatherstick sold by L.L. Bean which has been around for years. I grew up with one outside the kitchen window and have continued to have one close by all my life. Yes! Very accurate. Fun! Especially when the barometer drops as a hurricane approaches. Not very expensive. Treat yourself...

There was one nailed to my house by the previous owner. It is simple a stick with a small twig branching out of it. The twig changes from more straight to more bent, depending on the weather. I believe it is just affected by humidity. I think it doen't really predict anything, unless humidity predicts rain.

A more useful device is the weather glass, which indicates barometric pressure.

Jim

Here is a link that might be useful: Weather Glass