Aboriginal and Torres Strait Islander peoples observe the position of the stars in the sky and follow water, plant and animal cycles as ways of identifying seasonal phenomena. The seasonal calendars of different Aboriginal and Torres Strait Islander cultural groups demonstrate an understanding of the interdependence and interrelationships amongst living things. They use their calendars to predict seasonal changes and weather patterns to determine the availability of particular resources or the timing of journeys. The seasonal calendars vary according to geographic location, ecological context and cultural interpretation. Specific biotic events, often referred to as bio-indicators, can occur locally or over great distances, enabling accurate predictions of seasonal changes. For instance, the appearance of particular insect species may be an indication that the wet season is approaching, indicating that it is time to harvest yams. Observations of cyclical animal behavioural patterns are also important, for example when the D'harawal people of the Sydney basin area hear the mating cries of tiger quolls, the lillipilli fruit has started to ripen. Once the fruit starts falling, it is a sign for the people of this country to begin their annual journey to the coast, to seek out other seasonal resources. Seasonal calendars continue to be used by many groups today. The publication of First Nations' calendars has revealed the immense scientific knowledge held by the respective communities and has informed Western scientific understandings across a wide range of disciplines, for example, botany, zoology, ecology, meteorology and many more. The Bureau of Meteorology and the CSIRO have both worked with various groups to produce Aboriginal and Torres Strait Islander seasonal calendars. BOM has produced an interactive map, as of 2020 leading to a great deal of detail about 16 different Indigenous groups' calendars. The CSISO has as of this time documented the seasonal calendars of 9 Aboriginal groups in detail. Both sites provide downloadable and printable posters showing each group's calendar.
The Yolngu, the Aboriginal Australians of North-East Arnhem Land, identify six seasons. Non-Indigenous people living in the Top End usually identify two: the Wet and the Dry. The six Yolngu seasons, and their characteristics, are:
seasons do not follow a rigid cycle; timing is dependent on subtle changes in the weather with wind, rain and temperature. The cycles are part of katitjin-bidi or "knowledge trails" that lead groups to reliable sources of food and water. The seasons are named as follows by the WhadjukNoongar people of Perth:
In the Torres Strait Islands, the seasons are associated with the way the wind blows and changes in the environment. The four seasons based on the wind are known as Kuki, Zey and Nay Gay and Sager :
During Kuki, from January until April, the strong north-west winds and bring the wet season.
Southerly winds blow at different and unpredictable times during the year, and these times are known as Zey/Zei.
During Nay Gay/Naigai, from October through to December, northerly winds predominate, bringing high heat and humidity.
The people of Masig, known as the Masigalgal, are part of the Kulkulgal nation of the central Torres Strait. The timing and duration of these four seasons varies from year to year, and Masig islanders observe signs in the winds, weather, sea life, plants and animals that tell them when one season is expected to change to another. Community celebrations, hunting, gardening and cultural activities are based around this annual cycle of resource availability and renewal.
