Macquarie Island has an extreme oceanic climate with heavy cloud, strong westerly winds and an average rainfall of approximately 900 mm a year.
Temperatures are much milder than the continental stations with the averages above freezing and ranging between 3°C and 7°C. The ocean temperature of between 3°C and 5°C moderates the air temperature, with extremes recorded on the island being +13°C in January and −9°C in July and August.
Rain and snow are frequent, with only a few days each year with no precipitation.
Days can be quite sunny in December and January but the winter months are generally cloudy.
During the peak of summer, there are only about four hours of darkness.
The wind is almost constant on the island, averaging around 25 km/h throughout the year. Low pressure systems passing the island produce winds that gust to over 170 km/h.
Tides are measured for many different research and operational purposes. Such measurements have a practical value in determining sea level for mapping elevations and ocean depths, tidal predictions for shipping, and in the calibration of satellite altimeters.
Tide measurements also have a research value. Sea level data helps us understand long-term climate change as well as continental readjustment, heat transfer across the continental shelf, and other oceanographic phenomena including observation of Southern Ocean oscillation.