The March equinox, an astronomical event marking the moment the sun crosses the celestial equator, occurred on Friday, March 20, 2026. The event brought intensified sunlight to Indonesia as the sun positioned itself directly above the equator.
The term “equinox” originates from the Latin words equinoctis or equum, meaning “equal,” and noctis, meaning “night,” according to the National Research and Innovation Agency (BRIN). This literally describes the condition where both the Northern and Southern Hemispheres receive equal amounts of radiation, both in magnitude, and duration. This occurs due to the fact that neither hemisphere is tilted towards or away from the sun.
During the equinox, the sun appears directly overhead (at the zenith), causing shadows of upright objects at the equator to momentarily disappear. Pontianak, West Kalimantan, is known as the “Equator City” because it lies on the 0-degree latitude line. Observers there experienced the sun directly overhead at midday, a phenomenon often referred to as “day without shadows.”
From an observation of the Solar System outside of Earth, the Earth’s axis of rotation is perpendicular to the direction of sunlight. This causes the line between day and night to coincide with lines of longitude on the Earth’s surface, resulting in nearly equal day and night lengths across the globe. Though, atmospheric refraction can influence these durations.
The sun crosses the equator twice each year, once in March and again in September. The March equinox marks the beginning of the autumn season (autumnal equinox) in the Northern Hemisphere and the beginning of the spring season (vernal equinox) in the Southern Hemisphere. In Indonesia, the March equinox signals the transition from the rainy season to the dry season, while the September equinox marks the transition from the dry season to the rainy season.
Humans have observed the sun’s movements for millennia, often incorporating the equinoxes into cultural and religious traditions. For many ancient civilizations, the sun’s shifts determined the start of seasons and the timing for planting and harvesting. In Japan, both equinoxes are public holidays traditionally used to honor ancestors and deceased loved ones. The equinoxes are also marked by numerous ancient monuments, such as the Angkor Wat temple complex in Cambodia, where the sun rises directly over the central temple during the equinox.
While Indonesia does not experience distinct seasons like subtropical countries, it still feels the effects of the equinox. When the sun is directly above the equator, the amount of radiation received by the Earth’s surface is maximized, potentially leading to higher temperatures, especially with clear skies and minimal cloud cover.
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