Is weed legal in australia?

KINDA

Recreational
Decriminalized in Northern Territory and South Australia.Legal in Australian Capital Territory for personal use but not for sale.
Medical
Legal at federal level and in all states.
Notes
In September 2019, the Australian Capital Territory became the first state or territory of Australia to legalize recreational use of cannabis. Since 31 January 2020 residents have been allowed to grow two plants and possess 50 g, though sales or other transfer is prohibited, including cannabis seeds. Federal law also remains enforceable.

Glossary

Possession
In the context of cannabis laws, "possession" refers to having physical control over cannabis products. Laws often specify the amount one can possess, commonly in terms of weight (e.g., ounces, grams). Penalties for possession can range from fines to imprisonment, depending on jurisdiction and the amount possessed.
Decriminalized
Decriminalization means that possession of a small amount of cannabis for personal use is not a criminal offense, but may still be subject to a fine or other administrative penalties. It's a middle ground between full legalization and criminalization. Decriminalization aims to reduce the social and economic costs of enforcing cannabis prohibition, such as arrests and imprisonment.