What makes the passing of the seasons so different near the equator

The 23.5-degree tilt of the Earth's axis modifies the incidence of sunlight on the hemispheres and gives rise to the astronomical seasons (Illustrative image Infobae) In Quito, at 2,850 meters above sea level, temperatures can be cool for much of the year. However, that condition is linked mainly to altitude and does not contradict a central feature of tropical latitudes: near the equator, the four traditional seasons are barely distinguishable by temperature. In that band of the planet, the climate calendar is usually marked by rain, humidity and cloudiness, rather than by the succession of a cold winter and a hot summer. The explanation begins with the position of the Earth relative to the Sun. Its rotation axis is tilted approximately 23.5 degrees with respect to the plane of its orbit, a factor that causes notable seasonal changes in middle and high latitudes. Near the equatorial line, on the other hand, solar radiation varies less over the twelve months and the length of the day remains close to 12 hours. For that reason, the annual thermal range is usually smaller than in regions such as Argentina. The solstices and equinoxes occur anyway, because they are global astronomical phenomena. The difference appears in their local impact, NASA notes. During the equinoxes of March and September, the Sun can be located practically directly over the equatorial line at midday. NASA explains that the equinox marks the moment when the center of the Sun crosses the plane of the Earth's equator. In Buenos Aires, the difference in daylight hours between June and December is evident and accompanies the contrast between winter and summer. In the equatorial zone, by contrast, that variation is small. Day and night last about 12 hours for almost the entire year, so the input of solar energy does not show the abrupt changes typical of temperate climates. The tilt of the Earth's axis remains the origin of the astronomical seasons. In June, the northern hemisphere is oriented more toward the Sun; in December, that position favors the southern hemisphere. However, proximity to the equator limits the variation in the angle at which the sun's rays arrive. Thus, temperatures can remain high or moderate without forming four clearly differentiated thermal periods. This does not mean the weather is the same every day. Cloudiness, winds, storms and precipitation change throughout the year. In many tropical zones, the most useful indicator for recognizing the annual cycle is the alternation between wet and dry months. NASA points out that the 23.5-degree tilt of the Earth's axis modifies the incidence of sunlight on each hemisphere. That mechanism explains why the contrasts between summer and winter increase as the distance from the equator grows. Instruments installed near the equator record solar radiation throughout the year, a factor that helps explain the small thermal difference between the seasons (Illustrative image Infobae) The Intertropical Convergence Zone (ITCZ) is an atmospheric band near the equator in which the trade winds of both hemispheres converge. That convergence forces warm, humid air to rise; as it cools at altitude, it favors the formation of clouds, downpours and storms. Its location changes throughout the year. The ITCZ shifts north and south in response to the seasonal movement of maximum solar radiation. For the territories it passes over, that path can define the beginning or end of the rainy season. In areas closest to the equator, two peaks of annual rainfall can be recorded, linked to the passage of this band in its seasonal movements. The United States National Oceanic and Atmospheric Administration (NOAA) indicates that the ITCZ is responsible for the wet and dry seasons in the tropics. At greater distance from the equatorial line, the two rainy periods can merge into one main season, followed by a drier one. This dynamic explains why the categories of spring, summer, autumn and winter do not always accurately describe the tropical climate. In much of the tropical zones, rain, humidity and cloudiness order the climate calendar more than temperature changes (Illustrative image Infobae) The case of Ecuador shows that latitude is decisive, although it is not enough to anticipate the weather of each region. The country brings together the Pacific coast, the Andes mountain range, the Amazon and the Galápagos archipelago. The reliefs, altitudes and ocean currents introduce marked climatic differences. In the highlands, elevation substantially modifies temperatures. Quito, despite its proximity to the equatorial line, has a cooler climate than coastal cities due to its altitude. The region usually goes through a rainier period between October and May, in addition to relatively drier months between June and September, although those conditions vary according to the valley and locality. On the coast, a warm and rainy stage alternates with a drier and cooler one. The Amazon receives abundant rainfall throughout the year, with months of greater intensity. Galápagos, in turn, combines a warm and humid period with a cooler and drier one. Altitude, relief and ocean currents, including the Humboldt Current, modify local conditions. To claim that in Ecuador "there are no seasons" simplifies a diverse climate system. The country shares the astronomical cycles with the rest of the planet, but over much of its territory the clearest sign of the passing months is rain. The ITCZ, the mountains and the ocean explain why different climatic landscapes can coexist a few hundred kilometers apart.