The primary significance of the Antarctic Circle is astronomical. It marks the northernmost latitude in the Southern Hemisphere where the sun can stay above the horizon for a full 24 hours—a phenomenon known as the . Conversely, during the winter solstice, it is the northernmost point where the sun does not rise at all, resulting in Polar Night .
The sun remains below the horizon at noon. Geography and Climate antarctic circle
The sun remains visible at midnight.