For many individuals growing up in Indonesia, Malaysia, the Philippines or other Southeast Asian countries, the query often arises: why is there no winter, spring or autumn in our countries?
While people in Europe and North America know 4 frequently changing seasons, Southeast Asia has only two: the rainy season and the dry season.
It seems there may be a really specific scientific reason behind it, and all of it starts with one thing: the equator.
Location determines every part
The key to this phenomenon lies in a fundamental factor: how sunlight falls directly on the Earth’s surface. Because the Earth is spherical, the intensity of sunlight reaching any region depends largely on its distance from the equator.
In equatorial regions, the sun is nearly at all times almost overhead all yr round. As a result, the sun’s energy is targeting a smaller area, making it more intense and producing consistently higher temperatures.
However, the further the situation is from the equator towards the poles, the greater the angle of sunlight. The same amount of solar energy is distributed over a much larger area, reducing its intensity and leading to lower temperatures.
A transparent illustration of this could be seen throughout the equinox, when the sun is directly above the equator, in order that is where the strongest and most direct sunlight reaches. However, in cities far to the north, corresponding to Anchorage, Oslo and Saint Petersburg, the sun stays much lower within the sky. It rises only a 3rd of the way in which above the horizon, not overhead.
Because of the smaller angle, sunlight spreads more and appears weaker, giving these places only half as much heat as areas near the equator.
Southeast Asia just isn’t only situated near the equator, but a part of it’s directly crossed by it. The equator runs through each the land and waters of Indonesia and the waters of island nations corresponding to the Maldives and Kiribati.
Other countries within the region are very near it, including Malaysia, Thailand, Vietnam and the Philippines. Thanks to this geographical location, your complete region receives consistently high levels of solar radiation all year long.
Two seasons which might be actually rather more complex
Since the intensity of sunlight in Southeast Asia doesn’t change much all year long, temperatures remain relatively stable. Rainfall changes, creating the 2 important seasons within the region.
Warm air across the equator consistently rises, cools and releases moisture in the shape of heavy rainfall. This process produces long rainy seasons and makes tropical regions the biggest rainforests on the planet, including Southeast Asia.
Interestingly, high humidity also has a natural cooling effect, which is why equatorial areas will not be actually the most well liked places on Earth, despite the fact that they receive essentially the most direct sunlight.
Local geography can transform this pattern. For example, Mount Kilimanjaro is just about 330 kilometers from the equator, yet its summit is roofed in ice because of its high altitude.
In South America, the Andes lie near the equator but border the Atacama Desert, the driest desert on the planet.
This shows that being near the equator doesn’t robotically mean that it’s hot and humid. Elevation, wind patterns and proximity to the ocean play major roles in shaping the local climate.
Fun fact: why big storms avoid the equator
There’s an interesting phenomenon that always goes unnoticed: hurricanes and cyclones almost never form directly on the equator, despite the fact that the region is hot and humid – conditions seem ideal for giant storms.
The reason lies within the Coriolis effect. As the Earth rotates, different parts of its surface move at different speeds depending on their position.
Points on the equator move at about 1,700 kilometers per hour, while areas closer to the poles move much slower. This difference in speed causes the moving air to bend and swirl, which helps create cyclones.
In the Northern Hemisphere, cyclones rotate counterclockwise, while within the Southern Hemisphere they rotate clockwise. However, right on the equator this deflection effect is nearly non-existent.
As a result, the air doesn’t have enough “push” to begin swirling and grow to be a big storm. Therefore, tropical cyclones are inclined to form barely farther from the equator relatively than directly on it.
