Australia & Oceania

Oceania spans from the tropics of Hawaii and Papua New Guinea, just north of the Equator, to the southern tip of New Zealand near 47°S and on to the subantarctic islands further south, and from the tropical rainforests of Melanesia to the heart of the Australian Outback. Northern Australia and the Pacific high islands sit in tropical savanna and tropical rainforest, with a sharp wet-and-dry rhythm driven by the Australian monsoon.

The interior of Australia is a vast hot desert and semi-arid expanse — much of it under 250 mm of rain a year — while the southern coasts shift into Mediterranean climates around Perth and Adelaide, humid subtropical along the east coast, and oceanic in Tasmania and most of New Zealand.

The Southern Alps and the Great Dividing Range, with the surrounding ocean, shape the strongest regional contrasts. The Southern Alps split New Zealand into a hyper-wet west — Milford Sound and Fiordland record more than 6,000 mm a year — and a dry rain-shadow east where parts of Central Otago receive only around 350–400 mm.

The northeast Queensland coast is among the wettest places in the southern hemisphere, with Mount Bellenden Ker logging more than 12,000 mm in its wettest year. Oceania is also one of the most ENSO-sensitive regions on Earth: El Niño typically brings drought to eastern Australia and unsettled weather across the central Pacific, while La Niña reverses the pattern. Tropical cyclones strike the islands and northern Australia during austral summer, and the subtropical ridge plus föhn-style westerlies keep the dry belts in place year-round.

Our archive covers 2 cities across Oceania with daily ERA5 reanalysis data going back to 1940. The warmest July averages occur in Sydney, around 15.8°C, while Melbourne records the coldest January nights near 14.5°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1°C, alongside hotter heatwaves, more intense bushfire seasons, and rising seas that are reshaping low-lying Pacific atolls.