🇹🇼Taiwan

Taiwan (36,193 km²) is a mountainous subtropical-to-tropical island lying 180 km off southeast China's coast between 22°–25°N, 120°–122°E, bisected by the Central Mountain Range rising to 3,952 m at Yu Shan (Jade Mountain), East Asia's fourth-highest peak.

The island's climate spans three Köppen zones: tropical monsoon (Am) in the far south, humid subtropical (Cfa) dominating the western plains and northern coast, and humid continental (Dfb) 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 averaging 2,500 mm across windward eastern slopes and 1,800 mm in western lowlands, 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 16°C in high-altitude Alishan to 25°C in tropical Kaohsiung, with Taipei averaging 23.6°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 mountains with slopes exceeding 30°, creating flash-flood-prone catchments. Climate change is accelerating dramatically: Taiwan's mean temperature has risen 1.6°C since 1911—more than double the global average—with projections indicating 3°C warming 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, elevation 10 m) averages 28.5°C in July and 16.1°C in January 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 Taiwan's deadliest weather disaster: stalling over southern Taiwan for four days, the slow-moving storm dumped a world-record 2,900 mm in 48 hours on Alishan, triggering the Xiaolin village landslide that buried approximately 500 people in seconds when an entire mountainside collapsed, with total fatalities exceeding 700 and economic losses surpassing $3.3 billion USD.

Typhoon Doksuri (July 2023) brought extreme rainfall exceeding 500 mm in 24 hours to northern counties, triggering evacuations and landslides, followed by Typhoon Saola (August 2023) which forced mass evacuations across eastern Taiwan as 1,000+ mm rainfall threatened communities.

Typhoon Gaemi (July 2024) intensified rapidly to Category 4 strength, delivering severe flooding to Kaohsiung and Pingtung counties with over 800 mm in two days, killing 11 and causing widespread agricultural devastation. The exceptional 2021 drought—Taiwan's worst in over 56 years—saw reservoirs including iconic Sun Moon Lake drop to under 10% capacity by April, forcing exceptional water rationing for 1.1 million households in Taichung and Tainan, halting semiconductor fabrication plants, and revealing centuries-old submerged temples and artifacts.

The severe 2020 drought similarly emptied reservoirs, exposing WWII-era bomb craters and triggering emergency desalination efforts. Taichung (west-central, elevation 84 m) receives less rainfall near 1,700 mm with hotter summers reaching 32°C. Kaohsiung (southern coast) averages 25°C year-round with 1,800 mm. Mountain stations like Alishan (2,200 m elevation) record 4,000+ mm and cool 11°C averages with frequent fog.

Taipei's urban heat island now raises nighttime temperatures 2–4°C above surrounding rural areas, intensifying heat stress during summer humidity. Sea-level rise projections of 0.4–0.7 m by 2100 threaten 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 3 Taiwanese cities with daily ERA5 reanalysis data going back to 1940. The warmest July averages occur in Taipei, around 30.8°C, while Taipei records the coldest January nights near 11.1°C. Comparing the last decade against the 1940–1970 baseline, mean temperatures across these cities have risen by about 1.7°C.