Thermometer
A thermometer measures temperature, giving readings in either the Celsius or Fahrenheit temperature scale. A basic thermometer uses a liquid or metal to gauge what the temperature is in its surroundings. Others are more complex, using digital sensors and electronic components to determine temperature in multiple areas at one time.
Barometer
Being able to measure air pressure is important when determining weather conditions, because it can indicate what type of weather is about to occur. Rising air pressure often means fair weather conditions are ahead while falling air pressure means the opposite. Barometers measure these fluctuations in air pressure.
Anemometer
An anemometer determines the speed of the wind. This device looks like a small turbine or windmill and utilizes cup-like objects attached to a rod that catch the wind and spin. The wind speed is determined by how fast the cup-like objects spin.
Rain Gauge
When trying to accurately measure rainfall, it is important to have a stable, set container that will not be prone to spilling or run-off. Rain gauges are built to catch and hold rain so that this accurate measurement can be taken. Some include markings on the side that allow you to see at a glance how much precipitation has fallen. Others are blank, requiring a ruler or other measuring device to be inserted into the container to determine the amount of precipitation.
Wind Sock/Vane
A wind sock, or wind vane, identifies the direction the wind is blowing by pointing in that direction. Wind vanes often are made of metal while wind socks are usually created from light, weatherproof materials such as nylon or plastic.
Hygrometer
A hygrometer takes a reading on the amount of moisture in the air to determine humidity. Complex digital hygrometers use electronic sensors to determine this, while old-style manual hygrometers would use something as simple as a human hair, which respond to high levels of humidity by lengthening.