Dogs and cats are notorious for knowing when a tornado or earthquake are imminent. Birds roost early and feed heavily before a rain or snow and pigs and squirrels gather more debris to insulate themselves from cold weather. Plants and certain fungi such as rainstars can accurately forecast the certainty of wet and dry weather. Chickweed, dandelions, bindweeds, wild indigo, clovers, and tulips all fold their petals prior to the rain. Rainstars, a type of fungus, opens up prior to a rain and closes in dry weather.
Mushrooms abound when the weather is moist as well as do mosses and seaweeds.
In fact, seaweeds exposed on the rocks at low tide seem to swell and rejuvenate in the high humidity proceeding wet weather. Not all of these sayings hold true every time under every circumstance, but you might be surprised at just how accurate they tend to be. I remember back to the blizzard of 1993 and how amazed my friends were when the previous fall I was able to predict to the week that we would be having an enormous snowfall that spring. To say the least, there were a lot of surprised people when we ended up being snowed in for a week with the blizzard of the century. There are a lot of signs for forecasting the weather a long way out with some of them being more accurate than others, but with all of them being controversial.