Weather & climate

Today it is raining, yesterday the sun was shining, and tomorrow a storm is forecast. All of that is weather: the state of the atmosphere right now, at this exact place. But when you say that summers in Italy are usually hot and dry, you are talking about something else: climate. The two terms get mixed up all the time, yet the difference is simple, and it matters.

The moment and the average

Weather is what you experience today: temperature, rain, wind and clouds on a particular day. It can change within hours. Climate, on the other hand, is the long term average of the weather at a place, usually averaged over 30 years. So a single cold day says nothing about the climate, just as a single good grade does not make you top of the class. Only when you look at many years together do you see the typical pattern of a place, for example the Mediterranean climate with hot, dry summers and mild, wet winters.

Reading climate graphs

A climate graph packs the climate of a place into a single picture. The horizontal axis shows the 12 months. A curve shows the average temperature of each month in °C, and bars show the average precipitation in millimetres. One thing matters here: the values do not come from a single year, they are averages over about 30 years. At a glance you can see when it is warmest, when most rain falls and whether there is a dry season. That is exactly why many people look at the climate graph of their destination before a trip.

Climate zones of the Earth

Because the sun does not heat the Earth equally everywhere, the Earth is divided into climate zones. Around the equator lie the tropics: hot all year round, often with plenty of rain. Next come the subtropics, which include the Mediterranean climate. In the temperate zone, where Germany also lies, four distinct seasons take turns. And at the poles lies the cold zone, where even in high summer the temperature rises only a few degrees above zero. Each zone has its typical plants, animals and ways of life.