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Weather Forecasting

Weather forecasting is the science of predicting the weather.

The people who predict or forecast the weather are called meteorologists.

How do meteorologists do their job?

A meteorologist uses several different things to predict the weather. They use:

  • Barometer: An instrument that measures the pressure of the air. If the air pressure is rising (getting higher), the weather will be calm and mild. If the air pressure is falling, the weather is going to be rainy or stormy.
  • Thermometer: a thermometer measures the temperature of the air.
  • Sling Psychrometric: measures the humidity in the air. Humidity is the amount of moisture in the air, so this instrument tells weather forecasters how much moisture is in the air. If the air is Moist air is heavier than dry air, so when the air is humid, we sweat more (or it shows more) because our sweat cannot evaporate in the heavy, moist air.
  • Windsock: tells you which direction the wind is blowing.
  • Rain gauge: measures how much rain falls to the ground.
  • Anemometer: measures how fast the wind is blowing.
  • Weather satellites and computers: tracks the weather patterns from high up in the atmosphere and collects the data so the weather forecasters can use it.
  • Radar: an electronic instrument used to track how much precipitation is falling, where it is falling, and which direction it is moving. Radar also tracks tornadoes, hurricanes, and other types of storms.



Weather forecasting terms

  • Air mass: a large body of air with the same moisture content and temperature as the surface of the earth directly below the air mass.
  • Warm front:An invisible line between a cold and warm air mass; one where the warm air is taking over the cold air.
  • Cold front: An invisible line between a cold and warm air mass; one where the cold air is taking over the warm air.
  • Stationary front: The line where a cold air mass and warm air mass meet but neither one takes over the other.
  • Trough:A large area of low pressure, which means a stormy area.
  • Dew point: The temperature of the air when water vapor starts to be pulled or condense out of an air mass. The condensation drops onto the ground—usually late at night into the early morning hours. The more moisture there is in the air, the higher the dew point will be.
  • Humidity: The amount of moisture in the air.

Before there were instruments to predict the weather

The use of instruments to predict the weather has been around for hundreds of years…in some places. But not all people groups had access to them. Instead, they depended on their eyes, ears and noses just like people did before there were any instruments for measuring the weather. Here are some of the ways they predicted the weather:

NOTE: These old-fashioned weather predictors are very accurate. After all, they use the sky and the earth to do so.

  • If the sky in the east is red in the morning, a dry air mass has passed and a moist air mass is following behind it. This means rain will soon follow.
  • If the sky is red in the west in the evening, it means a dry air mass is coming, which means calm weather.
  • If there is a ring around the moon, rain or snow will be coming within 3 days.
  • If you take a big, deep breath while standing outside, and are able to smell the dirt and/or the flowers more than usual, rain is coming.
  • Cows that lay down in the corner of a field close together means a storm is coming.
  • When birds are flying low to the ground, this means the air is heavy—rain or storms are coming.
  • When birds are flying high in the sky, the air is calm and the weather will be mild.
  • Crickets really do tell us the temperature with their chirping. Count the number of chirps for 15 seconds and add 50 to know how hot or cold it is.
  • If the smoke from a campfire travels straight up into the air, the weather will be fair. If the smoke bends and blows low to the ground, rain is coming.


Facts for Kids
Facts for Kids


Try a few of these old-fashioned weather forecasting techniques and see for yourself.