When water moves up the spout, expect stormy conditions; when water moves down the spout, good weather is on its way. This hand blown glass bulb contains trapped air that expands and contracts with changes in atmospheric pressure. Since 1643, many seamen have used this simple device to predict the weather. ~15 cm (6 inches) tall. Colors may vary. Read more on our Blog - What's the Weather? Check Your Weatherglass Barometer!