The weather is the atmospheric conditions that happen around us all the time. The weather may be cold, wet, dry, calm, stormy, hot, or cloudy. All of these features make up the weather and learning how to predict it is the job of a meteorologist.
Meteorologists are very important to us as they forecast weather patterns and allow us to plan ahead. This is the information that most people use to schedule events, go on vacations, and plan their lives. This is why reading the weather is extremely important, as it is a critical part of our lives.
The weather changes due to air pressure. Air pressure is made up of temperature and moisture which changes depending on geographic location. For example, the air pressure on top of Mt. Everest will be much different than in the UK. Pressure and temperature differences will occur due to changes in the sun such as angle from different latitude and longitude locations on the Earth. Temperature differences are easily seen when you look at a locations average temperature in relation with the equator.
Almost all of the weather phenomena that we witness occurs in the troposphere which is the lowest part of the atmosphere here on Earth. Some weather will occur in the stratosphere (above the troposphere) and can affect the weather that we see on the ground. For us humans, the troposphere is the most important as this is what we live in and this affects us all the time.
Tracking different air pressures, commonly refereed to as high pressure and low pressure is the basis to predict weather patterns. This helps meteorologists determine whether its going to rain or if it will be sunny on different days of the week. How many times do you see a meteorologist on TV pointing and talking about 'high pressure' and 'low pressure' moving in? This is the basis for weather forecasting and this difference in air pressure is what determines what weather conditions we will have.
Weather actually does more than just produce clouds, sunshine, rain, and snow. It also plays a huge part in shaping the Earth. This is called 'weathering; Weathering is when rocks and soil are broken down mostly due to rain. This is what causes unusually shaped rocks, and other choreographic features. This is not to be confused by 'erosion'. Erosion can also occur by natural streams and rivers as they cut away at the Earth. Erosion is the cutting away of the Earth's surface features from a moving substance such as water. Both Erosion and Weathering play a large part in shaping the Earth around us.
But, weather does not just occur here on Earth. Weather takes place in other planets, stars, and in space. Solar Wind is one of the most common examples of movement of mass that is ejected from the Sun all the time. Also, several planets experience dust storms and other weather phenomena. This phenomena is tracked by scientists all the time, just as meteorologists here at home track our weather.