I've heard all my life about different ways to tell if it would be a good day to go fishing. I remember the old timers tell about getting all loaded up for a day of fishing and then while driving down the road they would notice the cows would be laying down. Nothing to do then but turn around and go back to the house. Everyone knew the fish would not bite when the cows were laying down. I have a different approach as to whether it would be a good day to go fishing......I throw a rock in the lake, if it floats I go back to the house.