🇹🇼Taiwan

Taiwan (35,808 km²) is a mountainous subtropical-to-tropical island lying 180 km off southeast China's coast between 22°–25°N, 120°–122°E, with the Central Mountain Range forming its spine and the neighbouring Yushan Range rising to 3,952 m at Yu Shan (Jade Mountain), which makes Taiwan the world's fourth-highest island.

The island's climate spans several Köppen zones, including tropical monsoon (Am) in the far south, humid subtropical (Cfa) dominating the western plains and northern coast, and alpine tundra (ET) on the highest summits above 3,000 m where snow occasionally falls in winter. The East Asian monsoon governs annual rainfall: the southwest monsoon (May–September) brings intense convective storms and typhoons and most of the island's roughly 2,600 mm average annual rainfall, while the northeast monsoon (October–March) delivers persistent drizzle to northern Taiwan but leaves the southwest in a pronounced dry season.

Mean annual temperatures range from 11°C in high-altitude Alishan to 25°C in tropical Kaohsiung, with Taipei averaging 23.3°C. Taiwan ranks among Earth's most typhoon-exposed territories: an average of 3–4 typhoons strike annually, concentrated July–September when warm Kuroshio Current waters and low vertical wind shear favor rapid intensification.

The steep topography amplifies orographic precipitation and severe landslide hazards: narrow coastal plains transition abruptly to steep mountains, creating flash-flood-prone catchments. Climate change is accelerating: Taiwan's mean temperature has risen about 1.4–1.6°C over the past century, with further warming projected by 2100 under high-emission scenarios, while intensifying typhoons, prolonged droughts, and expanding Taipei's urban heat island threaten water security, agriculture, and coastal infrastructure.

Taipei (northern Taiwan, 25°N) sees July highs of about 35°C and January highs of about 19°C (nights near 14°C), with approximately 2,400 mm annual rainfall distributed year-round, peaking during the May–June plum rain (meiyu) season and typhoon months. The severe Typhoon Morakot (August 2009) remains the wettest and deadliest typhoon in Taiwan's recorded history: the slow-moving storm dumped a record 2,777 mm of rain, triggering the Xiaolin village landslide that killed about 400–465 people, with about 700–780 dead or missing and economic losses of about $3.3 billion USD.

Typhoon Doksuri (July 2023) brought extreme rainfall of up to about 700 mm to the mountains of southern and eastern Taiwan, triggering evacuations of more than 5,700 people, followed by Typhoon Saola (August 2023), which brought land warnings and school and work closures to southern Taiwan.

Typhoon Gaemi (July 2024) intensified rapidly to Category 4 strength, delivering over 800 mm of rain in two days to parts of Kaohsiung and killing at least 10. The exceptional 2021 drought, Taiwan's worst in 56 years, dropped iconic Sun Moon Lake about 12 m to a record low by April and forced water rationing in Taichung, Miaoli and Changhua, while water trucks carried industrial water to big tech companies.

The dry 2020, with no typhoon landfall, had already drained reservoirs. Taichung (west-central) receives less rainfall near 1,760 mm, with summer highs reaching about 33°C. Kaohsiung (southern coast) sees daytime highs from about 24°C in January to 33°C in July, with nearly 2,000 mm. Mountain stations like Alishan (2,413 m elevation) record about 3,900 mm and cool days, with highs of about 11°C in January and 19°C in July.

Taipei's urban heat island now raises nighttime temperatures above surrounding rural areas, intensifying heat stress during summer humidity. Projected sea-level rise by 2100 threatens to inundate low-lying western coastal plains, saltwater intrusion threatens aquifers, and warming waters push tropical species northward while bleaching coral reefs around Kenting and Penghu.

Our archive covers 27 Taiwanese cities with daily ERA5 reanalysis data going back to 1940. The hottest July afternoons are in Taipei, with average highs around 33°C, while Bade has the coldest January nights, with average lows near 13°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.6°C.