Weather Instruments

Meteorologist A meteorologist is a person who studies weather. They need many kinds of data before the weather can be predicted. The ability to make accurate weather forecasts depend on the information gathered from the various weather instruments.

Thermometers Thermometers measure air temperature. Most thermometers are closed glass tubes containing a liquid. When the air around the tube heats the liquid, the liquid expands and moves up the tube. A scale that shows the temperature is on or attached to the tube.

Barometers A barometer measures air pressure. The air in the atmosphere exerts a force called pressure that constantly changes due to moving weather systems When a barometer reading is high, weather is most likely fair. When a barometer reading is low, rainy weather is likely. .

Psychrometers Also called a hygrometer. A psychrometer measures relative humidity. Relative humidity is a measure of the moisture in the air. Two thermometers are used. A wet cloth covers the end of one. The other remains dry. The difference between the readings of the two determines the relative humidity in the air.

Anemometers Anemometers measure wind speed. The cups catch the wind, turning the dial attached to the instrument.

Rain Gauge A rain gauge measures the amount of rainfall as well as other forms of precipitation. Most rain gauges generally measure the precipitation in millimeters. The level of rainfall is sometimes reported as inches or centimeters.

Wind/Weather Vane A wind vane measures wind direction by pointing towards either the North, East, West, South, or a combination of directions.