Carbon dioxide freezes at -78.5 degrees Celsius or -109.3 degrees Fahrenheit under atmospheric pressures. The coldest (we know) it has reached in Antarctica is about -89 degrees C. However, dry ice will not form there. This is because it has a very low abundance in the earth's atmoshphere, about 0.04% by volume. When we reduce the partial pressure of CO₂ (make it dilute in air) the frezzing point becomes lower. Although some dry ice might form initially, it will immediately sublimate back into the gas phase. Another answer is that if you were to bring dry ice to antarctica on a cold night, it would still sublimate to form CO₂ gas (although much slower than at normal temperatures).