Taiwan's Climate Pattern

Understanding Taiwan’s Climate System

Taiwan’s climate is fundamentally shaped by its geographic position and topography. Situated between 22°N and 25°N latitude, the island lies at the intersection of tropical and subtropical climate zones, straddling the Tropic of Cancer which passes through Chiayi and Hualian County. This positioning, combined with the Central Mountain Range creates distinct microclimates across remarkably short distances.

The island’s climate cannot be understood through simple categorisation. Whilst Taiwan is often labelled as having a “subtropical” climate, this designation applies primarily to the northern and central regions. The south experiences genuinely tropical conditions, whilst the mountains host temperate and even alpine environments. This diversity means that within a two-hour journey, you might move from humid coastal lowlands to misty mountain forests where temperatures drop by 15°C or more.

By Region and Season

Due to global warming, the climate has become increasingly unpredictable. Therefore, the descriptions in this chapter are for reference only. They reflect what the typical weather used to be like, although conditions now vary much more drastically. In general, it’s becoming harder to experience distinct spring or autumn weather.

Northern Taiwan

Northern Taiwan experiences the most pronounced seasonal variation on the island. The defining characteristic here is the extended period of grey, drizzly weather during the northeast monsoon season.

Winter (December-March): This is the wet season for the north. The northeast monsoon brings persistent cloud cover and frequent light rain: not dramatic downpours, but rather the sort of penetrating drizzle that requires an umbrella daily. Temperatures typically range from 12°C to 20°C, though cold snaps can occasionally push temperatures below 10°C. The humidity combines with relatively modest temperatures to create conditions that feel considerably colder than the thermometer suggests, as most buildings lack central heating. This is when you’ll see Taiwanese people bundled in substantial winter coats, a sight that might seem unusual to visitors from genuinely cold climates but makes perfect sense in the damp conditions.

Spring (April-May): The transition period brings uncertainty. The weather begins to warm, with temperatures climbing into the low-to-mid 20s°C, but rain remains frequent. The plum rains typically arrive in May, bringing heavy rainfall that can persist for days. Humidity rises noticeably during this period.

Summer (June-September): Hot and humid, with temperatures regularly exceeding 32°C and feeling hotter due to humidity often above 80%. Afternoon thunderstorms are common: intense, brief downpours that arrive with little warning, drench everything, then pass. Typhoons are possible from July through September. Despite the heat, this is when the north sees its clearest skies and most sunshine.

Autumn (October-November): Many consider this the finest weather in northern Taiwan. Temperatures moderate to a comfortable 20°C–28°C, humidity decreases, and rainfall diminishes. Clear, pleasant days predominate, though the northeast monsoon begins to reassert itself by November.

Central Taiwan

Winter (December-March): Significantly drier than the north, as the Central Mountain Range blocks much of the northeast monsoon moisture. Temperatures are similar to the north (12°C-22°C) but with far more sunshine. Clear days are common, making this an excellent time for outdoor activities in the region.

Spring (April-May): The plum rain season affects central Taiwan but generally less intensely than the north. Temperatures rise into the mid-20s°C.

Summer (June-September): Hot and often the wettest period of the year for central Taiwan. Unlike the north, where the northeast monsoon brings winter rain, central Taiwan receives most of its precipitation during summer, primarily from afternoon thunderstorms and typhoons. Temperatures regularly exceed 33°C.

Autumn (October-November): Similar to the north: pleasant temperatures, lower humidity, and reduced rainfall. Arguably the best time to visit this region.

Southern Taiwan

Southern Taiwan experiences a genuinely tropical climate with limited seasonal temperature variation but marked differences in rainfall patterns.

Winter (December-March): Warm and notably dry. Whilst the north shivers under grey skies, the south enjoys temperatures of 18°C-26°C with abundant sunshine. This is the dry season, and rainfall is minimal. The psychological difference between north and south during winter months is substantial: southerners often find Taipei’s winter weather borderline depressing.

Spring (April-May): Temperatures climb towards 30°C. The plum rain season has less impact here than further north, though occasional rain occurs.

Summer (June-September): Intensely hot, with temperatures frequently exceeding 33°C and regularly reaching 35°C–36°C. The humidity makes conditions genuinely oppressive during midday hours. Summer is actually the wet season for the south, with most annual rainfall arriving through afternoon thunderstorms and typhoons. The southwest monsoon contributes moisture during this period.

Autumn (October-November): Temperatures remain warm (24°C-30°C) but become more tolerable as humidity decreases. Rainfall diminishes, though occasional heavy rain is possible.

Eastern Taiwan

Year-round pattern: The east receives moisture from both the northeast monsoon (winter) and typhoons (summer). Annual rainfall often exceeds 2,000mm and can surpass 3,000mm in some areas. Temperatures are similar to the south (slightly cooler in winter), but the consistent moisture creates a distinctly different feel.

Mountain Regions

Taiwan’s mountains create their own climate rules. Temperature decreases approximately 6°C for every 1,000 metres of elevation gain.

High mountains (above 3,000m): These areas experience temperate to alpine conditions. Winter brings snow to the highest peaks, with temperatures regularly below freezing from December through February. Even in summer, temperatures at 3,000 metres typically remain below 15°C, and conditions can change rapidly. Fog and sudden weather shifts are common year-round.

Mid-elevation mountains (1,000m-3,000m): These regions experience pleasant, mild conditions year-round, which is why many mountain resorts and tea-growing areas exist at these elevations. Temperatures are typically 10°C–15°C cooler than the adjacent lowlands. The northeast monsoon brings persistent fog and drizzle to mountains in northern Taiwan during winter, whilst southern mountains remain relatively clear.

Monsoon Systems

Taiwan’s climate is dominated by monsoon patterns: seasonal wind systems that reverse direction and bring markedly different weather conditions depending on the time of year. Understanding the monsoon is crucial to understanding Taiwan itself, as it fundamentally shapes not just the weather but the entire character of the island.

The Monsoon Phenomenon: Why Taiwan Is Uniquely Humid

The monsoon system represents one of Earth’s most important climatic phenomena, and Taiwan’s position makes it subject to the full force of the East Asian monsoon. To appreciate the monsoon’s significance, consider Taiwan’s latitude: between 22°N and 25°N. Look at other locations along this same latitude band around the world: the Sahara Desert in Africa, the Arabian Desert in the Middle East, the deserts of northern Mexico, and the arid regions of northern India before the Himalayas. These areas share Taiwan’s latitude but experience profoundly different climates: hot, dry, and often desert or semi-arid conditions.

Taiwan escapes this fate entirely because of the monsoon, which exists due to the fundamental thermal differences between large landmasses and oceans. During winter, the Asian continent cools rapidly whilst the Pacific Ocean retains heat, creating a pressure gradient that drives winds from land to sea. In summer, the pattern reverses: the continent heats dramatically whilst the ocean warms more slowly, drawing moist air from sea to land. This seasonal reversal, combined with Taiwan’s island position between the vast Asian continent and the even vaster Pacific Ocean, creates the moisture-rich environment that defines Taiwan.

The result is an island that receives abundant rainfall year-round, with most locations receiving 1,500mm–2,500mm annually, and some mountain areas exceeding 4,000mm. This moisture sustains Taiwan’s remarkable biodiversity, its lush mountain forests, its productive agriculture, and its distinctive landscape character. Without the monsoon, Taiwan at this latitude would likely resemble the arid landscapes found at similar latitudes elsewhere: dry hillsides, sparse vegetation, and water scarcity. Instead, the monsoon delivers such abundant moisture that Taiwan’s challenge is often managing excess water rather than scarcity¹.

This is not merely an academic point. The monsoon’s moisture explains why Taiwan looks and feels the way it does—why the mountains are perpetually green, why mould and humidity are constant domestic challenges, and why the air often feels thick and heavy. The monsoon is the fundamental reason Taiwan can support such dense vegetation and why, despite intensive development, the island remains remarkably green.

Northeast Monsoon

The northeast monsoon governs Taiwan’s weather from October through March, peaking in intensity from December through February. This system develops as cold, dry air from the Siberian high-pressure system moves southward across the Asian continent, gaining moisture as it crosses the East China Sea before striking Taiwan’s northeast-facing coasts and mountains.

The geographic impact is dramatic and visible. The northeast coast, particularly areas around Keelung and the northeast corner near Yilan, receives rainfall during this period, whilst areas in the rain shadow of the mountains remain relatively dry. Hsinchu, positioned where the Central Mountain Range bends inland, experiences powerful winds funnelled through the geographic gap, earning its reputation as the “windy city”. These sustained winds, combined with clear skies in the northwest, create ideal conditions for the region’s wind power generation.

The monsoon’s effects extend beyond precipitation. It brings cooler temperatures, with occasional cold surges dropping temperatures across the island, sometimes even bringing rare snow to high mountains or, extraordinarily, to elevations as low as 1,000 metres during intense events. The persistent cloud cover in northern Taiwan during this season affects mood and behaviour: you’ll notice locals treasure any appearance of blue sky during these months.

For travellers, understanding the northeast monsoon explains why winter itineraries shouldn’t simply replicate summer plans. The north’s best outdoor venues, like beaches, coastal hikes, mountain trails, often experience poor conditions from December through March, whilst the same period offers excellent weather in the south. The monsoon effectively divides the island into two different climate experiences for half the year.

Southwest Monsoon

The southwest monsoon operates from May through September, though its effects are generally less dramatic than its northeast counterpart. Warm, moisture-laden air flows from the South China Sea and Indian Ocean, bringing humidity and contributing to summer rainfall, particularly in southern and western Taiwan.

Unlike the northeast monsoon’s persistent rain, the southwest monsoon primarily enhances convective activity: it doesn’t necessarily bring continuous rainfall but increases the intensity and frequency of afternoon thunderstorms. The moisture it carries, combined with strong solar heating, creates the characteristic summer weather pattern: clear mornings giving way to towering cumulus clouds by early afternoon, then explosive thunderstorms that release enormous amounts of rain in short periods before clearing by evening.

The southwest monsoon also interacts with typhoons and tropical disturbances. When a typhoon’s outer circulation combines with southwest monsoon flow, the result can be exceptional rainfall, particularly in southern and central Taiwan. Some of Taiwan’s most severe flooding events have resulted from this interaction rather than from typhoons alone.

Natural Disasters

Taiwan’s position along the Pacific Ring of Fire and in the primary western Pacific typhoon track means natural disasters are an inherent part of the island’s reality. Understanding these phenomena helps travellers prepare appropriately rather than worry unnecessarily: these events are well-managed, and Taiwan has developed sophisticated systems for prediction and response.

Typhoons

Typhoons (tropical cyclones) are the most significant weather-related natural hazard affecting Taiwan. The typhoon season officially runs from June through October, peaking in July, August, and September. Taiwan typically experiences three to four typhoons annually, though not all make direct landfall.

Formation and tracking: Typhoons develop over the warm western Pacific Ocean and generally track westward or northwestward. Taiwan’s position makes it vulnerable to storms following various paths: some strike the east coast directly, others make landfall in the south or north, whilst some pass through the Taiwan Strait. The Central Mountain Range significantly influences typhoon behaviour², often weakening storms or causing them to stall, which can paradoxically increase total rainfall even as wind speeds decrease.

Impacts: Modern typhoons in Taiwan rarely cause casualties due to excellent forecasting and preparation systems, but they significantly disrupt daily life. The primary hazards are threefold:

Wind damage: Typhoons can generate sustained winds exceeding 150 km/h, with gusts reaching 200 km/h or more in the strongest storms. These winds tear down signage, uproot trees, damage buildings, and turn loose objects into dangerous projectiles. Coastal areas face particularly strong winds, and elevated locations experience even greater wind speeds.

Heavy rainfall and flooding: Heavy rainfall is often more destructive than wind, as typhoons regularly deliver 500mm–1,000mm of rain over 24–48 hours, with extreme events exceeding 2,000mm in mountain areas. This rainfall causes river flooding, urban inundation, and triggers landslides. Mountainous areas face risks of catastrophic landslides, whilst low-lying coastal and riverside areas may flood extensively.

Storm surge and coastal hazards: Typhoons can generate storm surges, as elevated sea levels pushed ashore by powerful winds, that inundate coastal areas. Whilst full-scale tsunamis from typhoons are rare, the combination of storm surge, high waves, and heavy rainfall creates significant coastal flooding risks. Eastern Taiwan’s coastline, facing the Pacific directly, experiences particularly powerful wave action during typhoons.

Foehn winds: A particularly interesting and sometimes dangerous phenomenon occurs when typhoons pass over the north. As the typhoon’s circulation forces moist air over the Central Mountain Range from west to east, the air rises, cools, and releases its moisture as rain on the western slopes. The now-dry air descends the eastern slopes, compressing and warming adiabatically. The result can be dramatic: whilst the west experiences rain, eastern Taiwan (especially Taitung) may experience sudden temperature spikes of 5°C–10°C, with temperatures occasionally exceeding 38°C–40°C, combined with extremely low humidity and strong, gusty winds. These hot, dry conditions are uncomfortable and can stress agricultural crops, increase wildfire risk in mountain areas, and create additional challenges during what is already a dangerous weather event.

Response systems: Taiwan declares typhoon holidays when storms approach, closing schools and businesses in affected areas. This isn’t a frivolous closure: it’s a pragmatic recognition that travelling during typhoon conditions is dangerous. Convenience stores and some restaurants often remain open even during typhoons, reflecting Taiwanese resilience, but travellers should stock supplies beforehand.

Traveller considerations: If a typhoon approaches during your visit, don’t panic. Follow local advisories, expect transport disruptions for 1–2 days, and avoid mountains, coasts, and riversides. Most importantly, be flexible: typhoons are unpredictable, and your carefully planned itinerary may need adjustment. Hotels and transport companies are experienced with these disruptions and generally accommodate necessary changes. Stay indoors during the storm, away from windows, and never venture onto exposed coastlines or riversides to observe the conditions: every year, preventable casualties occur from such decisions.

Plum Rains

The plum rain season occurs in May and early June, named for coinciding with plum ripening. This isn’t a single storm but a frontal system that stalls over Taiwan and surrounding areas, bringing persistent, heavy rainfall.

The meteorological cause involves the meeting of cold air from the north and warm air from the south along a quasi-stationary front. Rather than moving through quickly like typical fronts, this system lingers, sometimes for weeks, producing continuous rain and embedded thunderstorms capable of extreme rainfall rates.

Plum rains affect northern and central Taiwan most significantly. Daily life continues, as this is expected weather, not an emergency, but outdoor activities become challenging. The persistent rain can be psychologically wearing, particularly for visitors expecting tropical sunshine. River levels rise significantly, and landslide risk increases in mountain areas.

For travellers, the plum rain season suggests avoiding late May for northern Taiwan visits, or at least planning indoor alternatives. Museums, hot springs, indoor markets, and covered areas become more attractive during this period.

Flash Flooding and Landslides

Taiwan’s steep terrain and intense rainfall combine to create risks of rapid flooding and landslides. These hazards connect directly to the climate: the island’s geology can’t absorb the enormous quantities of water delivered by typhoons, plum rains, and intense thunderstorms.

Urban flooding: Cities, particularly in southern and central Taiwan, can experience flooding during extreme rainfall events. Taipei’s extensive flood control system, developed after devastating floods in the past, generally manages well, but lower-lying areas may still flood during exceptional typhoons. Southern cities, built on flatter terrain, are particularly vulnerable.

Mountain landslides: Taiwan’s mountains are geologically young, steep, and heavily fractured by earthquakes. Heavy rain saturates slopes, triggering landslides that can block roads, rivers, and occasionally impact communities. Mountain roads routinely close during and after heavy rainfall: these closures are necessary safety measures, not inconveniences.

The 2009 Typhoon Morakot disaster, which caused catastrophic landslides and flooding killing hundreds, fundamentally changed Taiwan’s approach to mountain safety. Authorities now close mountain areas more readily during heavy rain, and some areas deemed too risky remain permanently off-limits.

Traveller implications: Never attempt to cross flooded roads: water depth and current strength are deceptive. Respect mountain area closures. If you’re hiking and heavy rain begins, descend immediately if possible, or seek shelter and wait.

Earthquakes

Whilst not a climatic phenomenon, earthquakes represent another major natural hazard that travellers should understand. Taiwan sits at the convergence of the Philippine Sea Plate and the Eurasian Plate, making it one of the most seismically active regions on Earth. The island experiences thousands of earthquakes annually, though most are too small to notice. Significant earthquakes, those strong enough to cause damage or widespread awareness, occur several times per year, and major destructive earthquakes happen every few decades.

Earthquake characteristics: Taiwan’s earthquakes range from barely perceptible tremors to violent shaking capable of collapsing buildings. The 1999 Chi-Chi earthquake (magnitude 7.3) killed over 2,400 people and fundamentally changed Taiwan’s building codes and emergency preparedness.

Early warning system: Taiwan has developed one of the world’s most sophisticated earthquake early warning systems. The system detects the initial, faster-moving seismic waves (P-waves) and calculates the earthquake’s location and magnitude within seconds. It then broadcasts warnings via the Cell Broadcast Service before the slower, more destructive waves (S-waves) arrive. This provides advance warning ranging from approximately 10 seconds to one minute depending on your distance from the epicentre: not enough time to evacuate, but sufficient to take protective action.

Warning reception: If a significant earthquake is detected, everyone’s mobile phone in the affected area will emit a distinctive, loud alarm and display an earthquake alert message showing the expected intensity and countdown to arrival. This system requires no app installation or prior setup: it works through the Cell Broadcast Service, which functions even when mobile networks are congested. Foreign visitors’ phones will receive these alerts if they support Cell Broadcast functionality (most modern smartphones do).

What to do: When you receive an earthquake warning or feel shaking, the response depends on your location. Indoors, take cover under sturdy furniture (desks, tables) away from windows, or brace yourself in a doorway or against an interior wall. Do not run outside during shaking: falling debris poses greater risk than remaining inside modern buildings. Outdoors, move away from buildings, power lines, and other structures. If you’re on public transport, remain seated and hold on. After shaking stops, be prepared for aftershocks, which can continue for days or weeks.

Modern building safety: Taiwan’s post-1999 building codes require earthquake-resistant construction, and most modern buildings, particularly in cities, are designed to withstand significant shaking. Older buildings, particularly those built before 1999, pose greater risk. Hotels and major tourist facilities generally meet high safety standards.

Traveller perspective: Earthquakes are unsettling, particularly if you’ve never experienced one, but Taiwan’s preparedness is excellent. The early warning system, strict building codes, and public awareness mean that even significant earthquakes typically cause limited casualties. Most travellers will experience only minor tremors, if any. The key is understanding what to do rather than worrying about whether an earthquake will occur: the answer is that small earthquakes will definitely occur, but significant ones are unpredictable and, whilst possible, are managed risks rather than reasons to avoid visiting.

Climate Considerations for Travel Planning

Understanding Taiwan’s climate allows you to make informed decisions rather than simply following generic advice. Ask yourself: What activities interest you? How does your body respond to heat and humidity? Do you prefer crowds or quieter experiences?

For heat-sensitive travellers: Consider visiting October through April, avoiding the intense summer heat. Focus on northern Taiwan in autumn / winter when temperatures are moderate, or visit southern Taiwan in winter when it’s warm but not oppressive.

For those seeking beach and water activities: Summer (June-September) is warmest for swimming, but autumn (September-October) often provides better conditions: still warm but with clearer water and smaller crowds. Avoid northern beaches in winter.

For mountain hiking: Autumn (October-November) generally offers the most stable weather across the island. Spring (April-May) is beautiful but wetter. Summer brings afternoon thunderstorms that pose lightning risks on exposed peaks. Winter is excellent for low-to-mid elevation hiking but challenging at high elevations.

The key insight is that Taiwan’s climate isn’t a problem to overcome but a system to understand. The same monsoon that brings grey skies to Taipei in January creates perfect beach weather in Kenting. The summer humidity that feels oppressive at sea level makes Taiwan’s high mountains refreshingly cool. By understanding these patterns, not just memorising “best times to visit”, you can design an itinerary that aligns with Taiwan’s climatic reality rather than fighting against it.