South Pole Sun Sets March 23, Will Not Rise Until September 21

The geographic South Pole experienced its last sunset on 23 March, marking the end of the six‑month period of continuous daylight that begins at the March equinox. The sun will not rise again until 21 September, when the September equinox brings the start of the polar night. This pattern is a direct consequence of Earth’s 23.5‑degree axial tilt, which causes the southern hemisphere to be tilted away from the Sun during the austral summer and toward it during the austral winter.

During the six months of daylight, the Sun remains above the horizon at all times, creating a twilight that never fully disappears. Conversely, the six months of darkness are characterized by a prolonged period of night, with only a faint blue glow from the sky at its brightest. The transition dates—23 March and 21 September—are the precise moments when the Sun crosses the horizon, marking the shift between polar day and polar night.

These extreme seasonal cycles have significant implications for the region’s climate, wildlife behavior, and scientific research. As the South Pole continues to experience its long night, scientists plan to monitor temperature changes, ice melt, and the behavior of polar organisms that rely on the unique light conditions of the Antarctic environment.