A better understanding of polar sea fog is significant for human activities in polar regions, but the sea fog’s information is scarce on a larger scale and extended period. This study compared the visibility data collected from the Chinese Antarctic Expedition (from 30th to 35th) and the cloud variables in ERA5 reanalysis. The statistical analysis shows an apparent connection between reanalysis cloud base height and underway visibility observation, especially when the total precipitation is relatively small. We discussed the essential relationship between sea fogs and clouds. A new method to present the Antarctic sea fog in austral summer thus was suggested by using the cloud base height and precipitation from reanalysis. This method has some advantages compared with traditional sea fog identification and prediction methods. Using this method, we drew a map of sea fog’s occurrence and discussed the climatological and interannual variability of the Antarctic sea fog from 1979 to 2019. The South Pacific, Northern Ross Sea, and sea areas near the Antarctic Peninsula are more prone to sea fog episodes. The ratio of sea fog occurrence around the Antarctic has decreased since the 1970s.