The \(90\) degrees south latitude marks the South Pole, situated deep within Antarctica on the vast Polar Plateau. This massive sheet of ice, kilometers thick, combined with the high elevation, contributes significantly to making this region the site of Earth’s most severe climatic conditions. The climate is classified as an ice cap climate, reserved for areas perpetually covered by snow and ice with no average monthly temperatures above freezing.
Thermal Characteristics
Temperatures at the South Pole remain frigid throughout the year, with little seasonal relief due to the persistent lack of direct solar energy input. The annual average temperature hovers around \(-49.5\) degrees Celsius (\(-57\) degrees Fahrenheit). Even during the austral summer, the temperature rarely approaches freezing; the highest temperature ever recorded at the Amundsen–Scott South Pole Station was only \(-12.3\) degrees Celsius (\(9.9\) degrees Fahrenheit).
The extreme cold results from multiple factors, starting with the very low angle of the sun, which never rises more than \(23.5\) degrees above the horizon. This low angle means solar radiation is dispersed across a greater surface area and much of the incoming energy is reflected by the bright snow and ice. During the six months of continuous darkness, temperatures plummet as the ice surface continuously radiates heat into space without solar replenishment.
This continuous heat loss results in the lowest temperatures of the year, with the record low reaching \(-82.8\) degrees Celsius (\(-117.0\) degrees Fahrenheit). The combination of high altitude and lack of solar heating ensures that temperatures remain well below the point where carbon dioxide would freeze into dry ice.
Extremely Low Precipitation
Despite being covered by an ice sheet nearly three kilometers thick, the region at \(90\) degrees south latitude is classified as an extreme polar desert. The atmosphere holds very little moisture because of the extremely low temperatures, a fundamental constraint on humidity. This lack of atmospheric water vapor leads to minimal true snowfall, with moisture accumulation comparable to some of the world’s driest hot deserts.
The annual precipitation, measured as the water equivalent of accumulated snow, is estimated to be only about \(70\) millimeters (\(2.8\) inches). Much of the moisture that falls is not traditional snowflakes, but microscopic ice crystals known as “diamond dust.” These crystals form from the direct condensation of the small amount of humidity present in the air.
The accumulation of snow is highly influenced by wind that constantly relocates the light, dry precipitation. The movement of snow creates localized drifts that can cause structures to become partially buried over time. The environment is characterized by near-zero humidity, contributing to the classification of this icy expanse as the driest continent on Earth.
The Six-Month Light Cycle
The climate at the South Pole is dictated by Earth’s axial tilt, creating an unusual annual cycle of light and darkness. Due to its position directly on the axis of rotation, the pole experiences only one sunrise and one sunset each year. This results in a period of roughly six months of continuous daylight, followed by six months of complete darkness.
The sun rises around the September equinox and remains continuously above the horizon until the March equinox, completing a slow spiral around the sky. During this daylight period, the sun never sets, but it never climbs high, reaching a maximum elevation of about \(23.5\) degrees during the December solstice. This low angle significantly limits the heat energy the surface absorbs, contributing to the persistent cold.
Conversely, the six months following the March equinox plunge the region into perpetual night, broken only by moonlight and the occasional aurora australis. This extended period of darkness corresponds with the deep winter months, allowing temperatures to drop and stabilize at their most extreme lows without solar warming. The unique solar geometry directly controls the energy budget for the entire year, driving the major thermal shifts.
Elevation and Wind Patterns
The severity of the South Pole’s climate is compounded by its substantial elevation, which affects air temperature and pressure. The geographic pole rests on the Antarctic ice sheet at an altitude of approximately \(2,835\) meters (\(9,300\) feet) above sea level. This height places the Amundsen–Scott South Pole Station on a high plateau, resulting in lower atmospheric pressure and a colder ambient temperature than at sea level.
The high elevation means the air is less dense and holds less heat, intensifying the chilling effects. The average atmospheric pressure is significantly lower than standard sea level pressure, contributing to the physical harshness. This combination of altitude and persistent cold air masses creates a year-round climate defined by extreme physical conditions.
The wind patterns at the South Pole are generally more stable and less violent than those experienced at the coast. While Antarctica is known for powerful katabatic winds—gravity-driven flows of cold, dense air rushing down ice slopes—the pole sits on the relatively flat interior plateau. The average wind speed is moderate, typically around \(10.7\) to \(12\) knots, with fewer extreme gusts than are common at coastal stations.
These consistent, moderate winds, controlled by the slight slope of the snow surface, contribute to a significant wind chill factor. The wind’s primary effect is the constant redistribution of dry surface snow, which builds drifts around structures and creates near-surface blizzards known as whiteouts. The movement of air ensures that the perception of cold is magnified beyond the recorded air temperature.