Weather prediction is a very important profession. Knowing the weather is an important factor of planning our daily lives. The people who predict weather are scientists called Meteorologists.

Meteorologists monitor weather conditions and map positions of air masses circling the earth using satellite images and other technologies and equipment. Since air masses interact in a predictable way, meteorologists are able to predict weather patterns with some degree of accuracy. Many of these tools used are measuring tools: Doppler radar and high-altitude balloons are used to collect data, Barometers measure the air pressure, Anemometers are used to measure wind speed, Psychrometers, or wet bulb thermometers, measure relative humidity, Thermometers measure the air temperature, and rain gauges are used to measure the amount of liquid precipitation.

Every weather prediction is based on the chance that the weather conditions will act together in a certain way. But forecasts can be wrong too. Some general patterns help meteorologists predict weather for a local area. For instance, most weather conditions across the United States move from west to east. Looking at the weather of an area in the west will give a clue to tomorrow's weather in an area east of that.

Other things that are known for affecting weather are geographical features such as the ocean and mountains. For example, if you live near the Atlantic Ocean, conditions to the east often influence your weather. And whether you live near the east coast or west coast, temperatures near the ocean may be higher than they are even short distances inland.