A severe hailstorm strikes Sydney, Australia causing A$2.3 billion in insured damages, the most costly natural disaster in Australian 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.

Sydney is the capital city of the state of New South Wales and the most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about 80 km (50 mi) from the Pacific Ocean in the east to the Blue Mountains in the west, and about 80 km (50 mi) from Ku-ring-gai Chase National Park and the Hawkesbury River in the north and north-west, to the Royal National Park and Macarthur in the south and south-west. Greater Sydney consists of 658 suburbs, spread across 33 local government areas. Residents of the city are colloquially known as "Sydneysiders". The estimated population in June 2024 was 5,557,233, which is about 66% of the state's population. The city's nicknames include the Emerald City and the Harbour City.

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.