The term weather describes the state of the air at a particular place and time.
Whether it is warm or cold, wet or dry, and how cloudy or windy it is, for example.
Throughout history, mankind has always been in awe of the weather. Ancient Civilisations considered natural disasters to be the work of the Gods and the weather still plays a big part in our lives today. It affects many of the things that we do, from the clothes we wear and the food we eat, to where we live and how we travel. As a result, the weather is of great interest to people everywhere, from meteorologists, the scientists who study it in great depth, to you and I in our everyday lives. In fact, one of the main topics of conversation is often what the weather will do next, particularly in areas such as New Zealand where the weather is very changeable and unpredictable. Think about how often you hear people discussing the weather.
The normal pattern of weather experienced in a particular area over a long period of time is known as the climate. The climate tells us how hot, cold or wet it is likely to be in different parts of the world at different times of year. For example, tropical countries have hot climates and the Antarctic has a cold climate.
The climate may include four seasons a year - spring, summer, autumn and winter - or a wet and a dry season. Our climate depends on our position on the earth and our distance from the sun. We will learn more about this in the Days and Seasons section.
Satellite image of stormWeather experts use computer technology and data from stations and satellites all over the world to predict the weather. By carefully monitoring weather conditions it is possible to predict when change is due - what we know as weather forecasting.
All the Earth's weather takes place in the lowest part of the atmosphere, which is called the troposphere. This extends upwards from ground level to about 8km at the poles and about 16km at the equator.