A storm dropped around 500,000 tonnes of hailstones on Sydney (examples pictured) and the east coast of New South Wales, causing about A$2.3 billion in damages, the costliest natural disaster in Australian insurance history.

The 1999 Sydney hailstorm was the costliest natural disaster in Australian insurance history, causing extensive damage along the east coast of New South Wales. The storm developed south of Sydney on the afternoon of Wednesday, 14 April 1999, and struck the city's eastern suburbs, including the central business district, later that evening.

Hail is a form of solid precipitation. It is distinct from ice pellets, though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fall in cold weather, while hail growth is greatly inhibited during low surface temperatures.

New South Wales is a state on the east coast of Australia. It borders Queensland to the north, Victoria to the south, and South Australia to the west. Its coast borders the Coral and Tasman Seas to the east. The Australian Capital Territory and Jervis Bay Territory are enclaves within the state. New South Wales' state capital is Sydney, which is also Australia's most populous city. In December 2024, the population of New South Wales was over 8.5 million, making it Australia's most populous state. Almost two-thirds of the state's population, 5.3 million, live in the Greater Sydney area.

The Australian dollar is the official currency and legal tender of Australia, including all of its external territories, and three independent sovereign Pacific Island states: Kiribati, Nauru, and Tuvalu. In April 2022, it was the sixth most-traded currency in the foreign exchange market and as of Q1 2024 the sixth most-held reserve currency in global reserves.