This report describes the historical weather record at the Pegasus blue ice runway (Antarctica) during 2011. This station has records back to December 2000.
Antarctica has a polar ice cap climate. The area within 25 mi of this station is covered by oceans and seas (100%)
Daylight saving time (DST) was not observed at Antarctica during 2011.
2011 was not a leap year, so it has 365 days and no February 29th. The first leap year before 2011 was 2008 and the first after is 2012.
The summer and winter solstices and the spring and fall equinoxes mark the passing of the seasons. They fall on nearly the same day each year, with differences of a day or two depending on the year. In 2011 they occurred on:
|Spring Equinox||Friday, 23 September 2011.|
|Summer Solstice||Thursday, 22 December 2011.|
|Fall Equinox||Sunday, 20 March 2011.|
|Winter Solstice||Tuesday, 21 June 2011.|
The hottest day of 2011 was January 17, with a high temperature of 34°F. The hottest month of 2011 was December with an average daily high temperature of 26°F.
The coldest day of 2011 was August 21, with a low temperature of -45°F. The coldest month of 2011 was June with an average daily low temperature of -42°F.
The longest freezing spell was from December 4 to December 24, constituting 21 consecutive days with temperatures strictly below freezing.
The clearest month of 2011 was January, with 13% of days being more clear than cloudy.
The cloudiest month of 2011 was January, with 81% of days being more cloudy than clear. The longest spell of cloudy weather was from January 2 to January 16, constituting 15 consecutive days that were cloudier than they were clear.
This station provides hourly reports of significant weather events at and around the station, but does not report the quantity of precipitation at the station itself. This is common for weather stations located outside of the United States, and for a small subset of stations in the United States that are located at lesser used and smaller airports.
This station reports when significant weather events (including precipitation) are visually observed at or near the station. Such events do not always correspond to measured quantities of liquid equivalent precipitation, such as when the event is near by not at the station, or in the case of solid precipitation that does not melt in the collection basin.
The day in 2011 with the most precipitation observations was January 26. There were 24 hourly weather reports that day (out of a maximum of 24) in which some form of precipitation was observated at or near the station. The month with the most precipitation observations was January, with 188 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from March 1 to August 28, constituting 181 consecutive days with no observed precipitation. The months March, April, May, June, July, September, October, and November were completely without observed precipitation.
The month with the largest fraction of days with at least some observed precipitation was January, with 58% of days reporting some observed precipitation.
In this section we consider only those weather reports that indicate liquid precipitation. For the purposes of this analysis, we include thunderstorms even though some thunderstorms are not accompanied by liquid precipitation.
The month of 2011 with the largest number of those reports was January, with a total of 0 reports. The day with the largest number of those reports was January 1, with a total of 0 reports.
This station reports when snow is observed falling but does not report the quantity of snow that has fallen or the depth of snow on the ground.
In this section we consider hourly weather reports that contain an observation of falling snow. These reports do not necessarily correspond to accumulation.
The first reported snow fall in 2011 was on January 3; the last was on December 22. The month of 2011 with the largest number of those reports was January, with a total of 188 reports. The day with the largest number of those reports was January 26, with a total of 24 reports.
Humidity is an important factor in determining how weather conditions feel to a person experiencing them. Hot and humid days feel even hotter than hot and dry days because the high level of water content in humid air discourages the evaporation of sweat from a person's skin.
When reading the graph below, keep in mind that the hottest part of the day tends to be the least humid, so the daily low (brown) traces are more relevant for understanding daytime comfort than the daily high (blue) traces, which typically occur during the night. Applying that observation, the least humid month of 2011 was June with an average daily low humidity of 29%, and the most humid month was January with an average daily low humidity of 73%.
But it is important to keep in mind that humidity does not tell the whole picture and the dew point is often a better measure of how comfortable a person will find a given set of weather conditions. Please see the next section for continued discussion of this point.
Dew point is the temperature below which water vapor will condense into liquid water. It is therefore also related to the rate of evaporation of liquid water. Since the evaporation of sweat is an important cooling mechanism for the human body, the dew point is an important measurement for understanding how dry, comfortable, or humid a given set of weather conditions will feel.
Generally speaking, dew points below 50°F will feel a bit dry to some people, but comfortable to people accustomed to dry conditions; dew points from 50°F to 68°F are fairly comfortable to most people, and dew points above 68°F are increasingly uncomfortable, becoming oppressive around 77°F.
To take some examples, and basing our categorization on the daily high dew point in 2011, January had 29 dry days, no comfortable days, and no humid days; April had no dry days, no comfortable days, and no humid days; July had no dry days, no comfortable days, and no humid days; and October had no dry days, no comfortable days, and no humid days.
The highest sustained wind speed was 46 mph, occurring on August 31; the highest daily mean wind speed was 33 mph (August 31); and the highest wind gust speed was 60 mph (August 31).
The windiest month was August, with an average wind speed of 12 mph. The least windy month was June, with an average wind speed of 4 mph.
This station did not reliably report the visibility during 2011.
The cloud ceiling is the altitude of the lowest layer of clouds that are at categorized as broken (mostly cloudy) or overcast (cloudy). If no such cloud layer exists then the ceiling is unlimited and no value is reported.
The day of 2011 with the lowest average cloud ceiling was January 24, with an average cloud ceiling of 49'. The month with the lowest average cloud ceiling was December, with an average cloud ceiling of 6125'. The month of March has the highest average cloud ceiling, with an average cloud ceiling of 9932'.