Climate  Climate is the average or usual weather pattern that occurs in a region over a long period of time.

Weather  Weather is the day-to-day changes in temperature, wind, precipitation, humidity, and air pressure.

Key Terms  Winds  Clouds  Precipitation  Barometric Pressure  Temperature  Humidity

Wind  Wind is air that moves from one place to another.  Air that grows warmer rises upward. This is called an updraft. Cooler air flows to the surface to fill up the space vacated by the rising air. This cooler air also heats up and rises.

Clouds  Clouds are water droplets or ice particles floating in the atmosphere. Clouds usually form when warm air rises, cools and condenses.

Types of Clouds

Precipitation  Precipitation is water as a water, liquid, or solid that falls to Earth. Precipitation includes rain, snow, sleet, hail, and freezing rain.

Barometric Pressure  Barometric Pressure is that air pressure that is caused by the weight of all the air in the atmosphere pressing down on Earth.  A "rising" barometer indicates increas­ing air pressure; a "falling" barometer indicates decreasing air pressure.  As a very loose rule, a high-pressure area will be clear, and a low-pressure area will be cloudy and rainy.

Temperature  Temperature is the measurement of heat in a substance.  Temperature is measure in Fahrenheit and Celsius.  Fahrenheit remains the official scale in several countries: United States, Cayman Islands, Palau, Bahamas and Belize.

Humidity  Humidity is the amount of water vapor in the air.  A reading of 100 percent relative humidity means that the air is totally saturated with water vapor and cannot hold any more, creating the possibility of rain.  Most people with instruments to measure air humidity are measuring the humidity of this "lower" air, which will likely range from % humidity during a rainstorm.

Weather Data Collection Instruments  Outdoor Thermometer  Anemometer  Barometer  Rain Gauge  Hygrometer  Weather Vane

Outdoor Thermometer  An Outdoor Thermometer is an instrument for determining temperature located outside.

Anemometer  An Anemometer is an instrument for measuring wind speed.

Weather Vane  A Weather Vane is an object that is usually put outside and that has an arrow that turns as the wind blows to show the direction of the wind.

Barometer  A Barometer is an instrument for determining the pressure of the atmosphere (High and Low Pressure) and for assisting in forecasting weather.

Rain Gauge  A Rain Gauge is an instrument for measuring the quantity of precipitation.

Hygrometer  A Hygrometer is an instrument used to measure relative humidity.