In meteorology a distinction is made between weather and climate. The term weather refers to current weather events. The word climate, however, describes the long-term weather pattern. In Central Europe, for example, there is a moderate climate. It is shaped by the 4 seasons. But that is not the case everywhere. In some areas there is a time-of-day climate.
What does that mean?
The annual climate describes the long-term cyclical fluctuations in temperatures, precipitation and wind conditions in a region. However, there are also areas on earth where the weather conditions are uniform all year round. This is especially true in the areas near the equator. There are hardly any seasonal changes in temperature there. It is often in the range above + 25 ° C, but it can also be lower at high altitudes.
There are hardly any differences between the individual months in terms of the weather in such areas. In the rainforest of the Amazon or the Congo, it rains almost at the same time every day. The temperatures fluctuate only a few degrees over the course of the year. On the other hand, temperature differences of 12 degrees and more can occur during the day. If the daily fluctuations in temperature exceed those of the annual deviations, one speaks in meteorology of a time-of-day climate. This means that the climate is determined by the time of day.
What does a time of day climate look like?
Sunrise occurs every day around 6 a.m. The days are the same all year round. Since the sun’s orbit is much steeper than in Central Europe, dawn and dusk are very short. It is still dark at 5:50 a.m. and the sun is already shining at 6:10 a.m. When it rises, the sky is mostly clear. If there is morning fog, it evaporates quickly because the sun’s rays are much steeper at the equator and transmit more energy. This also means much more intense evaporation. Moisture rises from the dense vegetation and the water and collects in clouds. They grow rapidly until they rain down. This happens almost every day and mostly at the same time.
There are areas where you can almost set the clock after the daily downpour. The rain almost always comes down in the form of thunderstorms. That is a strong understatement, because in Germany such thunderstorms would be called a downpour. The rain is heavy but doesn’t last long. After one, at most two hours, everything is over again. When the sun sinks lower in the afternoon, its radiation is no longer as intense. The clouds dissolve and the sky is clear again by evening at the latest.
The sun sets around 6 p.m. Just a few minutes later, night falls. Because of the lack of solar radiation, it then cools down a bit. Nevertheless, the temperatures remain above + 20 ° C, at least in places at sea level. There are exceptions in regions that are very high. It can get quite cool there at night even near the equator. This is because the thin air can store less heat. In arid regions such as the Atacama and Namib deserts, the temperature differences between day and night are also greater. The reason for this is the dry air. Since it hardly contains any water vapor, it can store little heat and cools down quickly after sunset.
What creates the time-of-day climate?
As with any weather, the driving force behind the daytime climate is the sun. It keeps the weather going all over the planet and is also responsible for this kind of climate, which seems strange to us. At the equator, the sun’s orbit is not subject to any changes over the course of the year. It always rises to the east around 6 a.m. At noon it reaches its zenith and then stands vertically in the sky. After that, its orbit begins to lean towards the west, until it finally sets around 6 p.m. Day and night are always the same length.
These uniform astronomical conditions also ensure that there are only minor fluctuations in temperatures and precipitation. Dry and rainy seasons, if they exist at all, are only slightly pronounced. The climate changes much more in the course of a day than in a year. Places with a daytime climate are, for example, Manaus on the Amazon in Brazil or Kinshasa, the capital of the Democratic Republic of the Congo, on the river of the same name, or Kampala, the capital of Uganda, not far from Lake Victoria.