In places in the northern and southern half of each hemisphere that are nearer the poles, the year is divided into four seasons based on temperature. They are spring, summer, autumn/fall and winter. Each period lasts about three months and is related to the position of the Earth in space. In winter, the Northern Hemisphere tilts away from the Sun. This means that the Sun does not rise high in the sky and only provides a little heat and light. In spring, the tilt of the Northern Hemisphere is moving towards the Sun and the weather is warmer. In summer, the Northern Hemisphere is tilted towards the Sun and the weather is hot. As the Northern Hemisphere tilts away from the Sun again in autumn/fall the weather becomes cooler.

In the Southern Hemisphere, in places like Australia, the pattern occurs at the opposite time of the year, so that summer in the Northern Hemisphere is winter in the Southern Hemisphere.

In some parts of the world close to the Equator temperatures do not change very much and frost is unknown. In these areas there are just two seasons – the wet and the dry season. In these places, such as India or the southern states of the USA, the temperature does not change as much as nearer the poles and plants could grow all year if the could get enough water. However, a long dry season usually stops plants growing. In these areas the wet seasons often starts with great storms, thunder and lightning. In India and some other places, the wet season starts very suddenly and it is called the monsoon.