Tropical zones

Maria is packing for her tropical vacation. We often use “tropical” to describe places that are sunny and warm, but not every warm place has a tropical climate. Tropical regions - the tropics - lie roughly in the middle of the Earth, closest to the equator. They experience direct sunlight all year round. They are also warm all year, with temperatures averaging between 20 and 30 degrees Celsius.

Because of all that sun and heat, the tropics don't experience four distinct seasons like much of the world does. The tropics have just two seasons: the wet season and the dry season. So what should Maria pack, exactly? Well, that all depends which tropical climate zone she's visiting. If Maria goes to a tropical rainforest zone, also known as a tropical wet zone, she’ll want to bring an umbrella.

Aside from a very short dry season, it rains almost all year round. These regions have the most predictable weather on Earth, with very little change between dry and wet seasons. Temperatures remain constant throughout the year: it’s always warm! And it rains a lot. In the world’s largest tropical rainforest, the Amazon, the average annual rainfall is over 2 000 millimetres!

Tropical rainforests’ hot and wet climate creates ideal conditions for many species of plants and animals. As a result, over half of the earth's animal and plant species can be found living in tropical rainforest climate zones. Not every tropical zone gets such frequent rain. In tropical regions such as southern Asia and West Africa, the climate is very dependent on seasonal wind systems called monsoons. A monsoon is a wind system that reverses its direction every six months.

Tropical regions that experience them are located in tropical monsoon climate zones. Summer monsoons bring large amounts of rainfall. Bangladesh is famous for its monsoons. The country receives nearly all of its rain for the whole year during the 5-month monsoon season, from June to October. So much rain in a relatively short period means that countries in tropical monsoon climate zones can be severely impacted by flooding.

So I’ll need all my rain gear to go to a tropical place? Well, not necessarily. There is another tropical zone. Regions in this zone are found between tropical rainforests - which receive a lot of rainfall every year - and desert regions - which receive almost no rain at all. In this climate zone there is a rainy and humid wet season, and a long dry season.

Because it does not consistently get water, this climate zone often features grasslands - savannahs - rather than thick jungle. That is why this climate zone is called the tropical savannah zone, or the tropical wet dry zone. People and animals living here rely on the rainy season, so during years when rains are light, they suffer through intense water shortages. In fact, many plants and animals adapt in different ways to cope with the dry conditions. For example here, in the Serengeti in Tanzania the baobab tree can store hundreds of litres of water in its trunk, so it doesn’t need frequent rain to grow.

Maria has lots to consider as she’s packing her bag! A tropical vacation doesn’t always mean T-shirts and shorts. The clothes Maria needs will depend on whether she’s going to a tropical rainforest zone, a tropical monsoon zone, or a tropical savannah zone. And - what time of the year she’s going — will it be the wet season or the dry season? Try to keep these things in mind, Maria.

Have a nice trip!