Seasons of Antarctica

Seasons are different all over the planet. You might be used to the four seasons – winter, spring, summer and autumn, or a wet season and a dry season. On the continent of Antarctica, there are only two seasons, winter and summer.

Rothera Research Station basking in the summer sun. Photo: Bethan Davies

In the southern hemisphere, where Antarctica is, summer and winter are at the opposite time of year to the northern hemisphere. Summer in Antarctica starts in October and ends in March, and winter starts in March and lasts until October.

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Goodbye summer sun! Sunset in Antarctic Sound, March 2012. Photo: Bethan Davies

Antarctic seasons change as Earth moves around the sun. Earth is a globe that spins around an axis. That axis is tilted. Because it is tilted, Antarctica and the south pole point towards the sun in summer and away from the sun in winter.

Earth’s orbit around the sun causes the seasons in Antarctica.

Daylight in an Antarctic Winter

When Antarctica is pointing towards the sun, in summer, there is sunlight all day long, and the sun does not set until the winter. This is often called Antarctic Day, with the Midnight Sun. You would be able to read a newspaper outside at midnight at the South Pole. If you’re camping in the Antarctic summer, it’s best to bring an eye mask!

In winter, it is dark all day long, and this is called Antarctic Night. Even at 12:00 noon, it will be pretty dark south of 80 degrees south. The sun may just peek above the horizon north of 80 degrees south.

Halley VI Research Station in Antarctic winter. The sun is just peeking above the horizon, but that’s as high as it will get until summer! Source: https://www.bas.ac.uk/media-post/midwinters-day-in-antarctica/

Temperatures in an Antarctic winter

Because the sun never rises, Antarctic winters are very cold. The average temperature across Antarctica during winter is -34.4°C. Even in summer, Antarctica is still really cold, with temperatures rarely above freezing (0°C), except at the coasts and extremities.

Even in summer, it’s still really cold! But not too cold for some recreational snowsports! Photo credit: Bethan Davies

Sea ice in the Antarctic Winter

In an Antarctic winter, it is so cold that the sea freezes, forming briney sea ice that surrounds the continent. In summer, most of the sea ice melts. The area of sea ice in winter is about six times as big as the area of sea ice in summer, with an average 3 million km2 in summer and 18 million km2 in winter.

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Icebergs caught in sea ice, viewed from the Twin Otter in early Summer, before the sea ice melts. Photo credit: Bethan Davies

At the end of summer, in March, the sea is warmest and the sea ice is smallest, called the sea ice minimum. At the end of winter, in September, the sea ice is biggest, known as the sea ice maximum.

Amount of sea ice in summer (March) and winter (September). Data from the National Snow and Ice Data Center (NSIDC).

People in an Antarctic winter

Antarctic seasons affect human and wildlife activity. Few people remain on Antarctica during the winter as it is cold and bad weather makes it difficult to get to and from research stations.

In summer, there is much more life on Antarctica, and melting sea ice means much more food available for fish, penguins and seals.

Dog sled racing to celebrate Midwinter’s Day on Antarctica… Except the dogs here are humans! Source: https://www.bas.ac.uk/media-post/midwinter-2018/

In Antarctica, some bases are occupied in the summer only. Others, such as Rothera and Halley, are occupied throughout the year. People that stay on Antarctica over winter are called winterers. They celebrate midwinter on 21st June, when Antarctica is furthest from the sun.

Traditional celebrations include games and sports such as an outdoor run or Winter Olympics, and a big meal together.

Once winter has come in Antarctica, it is very difficult to leave. Winterers must be entirely self sufficient, as evacuation from a winter base is very challenging. The base team will include doctors, engineers, carpenters, mechanics, chefs, and all kinds of skilled people who can keep the base running. Other people who might over-winter on a base include scientists, such as meteorologists or biologists.

Research bases around the Antarctic Peninsula. Of the British bases, Rothera is occupied all year around, but Fossil Bluff is occupied in the summer only.

Photographing Winter in Antarctica

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Dramatic skies at Rothera Research Station. Photo: Iain Rudkin https://www.iainrudkin.com/Polar-Life/

Check out loads more dramatic photos of all seasons in Antarctica from Iain Rudkin on his website! https://www.iainrudkin.com/Polar-Life/

The photogallery below shows photos from Ian Hey from his time at Halley Station over winter.