Alishan (Alishan National Scenic Area) weather in May

May in Alishan: nice, soaked, with muggy air — fine if you can take 28 rainy days.

Updated September 2026 · climate normals from ERA5 reanalysis

Alishan🇹🇼 Taiwan · Taiwan & Okinawa · National park70
  1. 81Jan
  2. 84Feb
  3. 82Mar
  4. 80Apr
  5. 70May
  6. 69Jun
  7. 71Jul
  8. 69Aug
  9. 68Sep
  10. 73Oct
  11. 84Nov
  12. 85Dec

#9 of 12 months in Alishan · #1029 of 1413 destinations to visit in May · comfort 70/100 (tier B)

Days
19°C
Nights
12°C
Wet days
28
Sun
9.2 h
Humidity
85%
Daylight
13 h
Alishan, Taiwan
Photo: Guilherme Christmann · Pexels

Traveller notes on Alishan in May

Taiwan forum threads are direct that late May marks the start of the plum rain season, bringing rain on roughly half the days through the following weeks, with fog at Alishan described as an almost daily occurrence even outside heavy rain spells. The more typical pattern posters described was sunny mornings followed by afternoon thunderstorms lasting an hour or two before clearing again, rather than sustained all-day washouts. One specific frustration flagged repeatedly: the famous Alishan sunrise is genuinely hit-and-miss on foggy mornings, so visitors chasing it were advised to build in a backup morning if possible, and to always carry a proper rain jacket or poncho.
ChiayiMountainRegular · May · 1 month ago · Read more on Tripadvisor ↗

Other months in Alishan

Alishan-forum threads on whether real winter wear is needed in January are unambiguous: yes, posters calling readings commonly single digits or close to zero, thick, puffy layers standing advice regardless of how mild Chiayi or Taipei feel. Regulars call a proper parka and thermal base layers genuinely useful, mornings and evenings considerably colder than the daytime peak. Posters describe mountain areas as running a few degrees cooler and windier than general figures suggest, Alishan's elevation adding a real chill. Regulars call the sunrise viewpoint specifically brutal before dawn, real cold-weather gear essential for the wait. Posters recommend layering rather than one heavy coat, temperatures climbing considerably once the sun is up. Regulars call the cypress forest walks still rewarding in January despite the cold, fewer crowds a genuine upside. The record: 11.9C days feeling like 11C, 4.9C nights, 96.2mm across nearly 17 days and 82 percent humidity.
AlishanJanuaryRegular · January · 1 month ago · Read more on Tripadvisor ↗
Alishan-forum threads on sunrise temperatures describe conditions at the summit viewpoint as genuinely cold regardless of how mild Chiayi feels below, posters calling readings in the single digits Celsius entirely plausible for the early wait. Regulars call the sunrise train departure around five-thirty standard, staying overnight strongly preferred over a lengthy pre-dawn drive up. Regulars describe daytime temperatures as considerably milder once the sun is up, a real layer system working better than one heavy coat given the swing. Posters call late February through June broadly the favored stretch, typhoon season from July into early October a real reason to avoid later months. Regulars recommend booking sunrise train tickets well ahead, capacity limited and demand high. Posters call the cypress forest walks worth the visit independent of the sunrise. The record: 17.2C days feeling like 18C, 9.9C nights, an extraordinarily high 182.5mm across nearly 24 days and 82 percent humidity.
AlishanAprilRegular · April · 1 month ago · Read more on Tripadvisor ↗
Alishan-forum threads on March weather describe daytime readings as generally mild but genuinely cold at night, posters citing single-digit overnight lows especially when a system moves through the wider region. Regulars call parka-style layers and proper thermal wear standing advice, mornings and right after sunset both considerably colder than the daytime reading suggests. Posters describe the famous sunrise viewpoint as running noticeably colder still, its higher elevation meaning conditions there rarely match a general Alishan forecast. Regulars call March genuinely good timing for cherry blossoms, the bloom regularly overlapping with this stretch. Posters describe fog and a passing shower as fairly common in the mountains despite the otherwise favorable reputation. Regulars recommend real cold-weather layers regardless of the lowland forecast. The record: 14.9C days feeling like 15C, 7.4C nights, an extraordinarily high 137.6mm across over 21 days and 80 percent humidity.
AlishanMarchRegular · March · 1 month ago · Read more on Tripadvisor ↗
Alishan-forum threads on sunrise viewing are direct results here are genuinely inconsistent, one traveler reporting a great sunset but an underwhelming, cloudless sunrise the same trip, another describing thick fog ruining the sunrise while catching a genuine sea of clouds elsewhere on the same itinerary. Posters call September part of the broader wet season, a real chance of lingering shower activity even as the worst of typhoon season winds down. Regulars recommend building at least two mornings into any stay to improve the odds of catching a clear sunrise, a single attempt genuinely a gamble this time of year. Layers are standing advice given how much temperatures swing between a mild afternoon and a genuinely cold pre-dawn wait. Posters call the forest railway and cypress groves worth the trip regardless of whether sunrise cooperates. The record: 19.2C days feeling like 20C, 13.4C nights, an extraordinarily high 219mm across nearly 23 days and 88 percent humidity.
AlishanSeptemberRegular · September · 1 month ago · Read more on Tripadvisor ↗

Add your own note from Alishan's card on the map.

Alishan climate normals — May

Daytime high19°C / 66°F😎 nice
Nighttime low12°C / 54°F
Feels like (high)20°C / 68°F
Rainfall310 mm / 12.2 in⛈ soaked
Rainy days28 days
Humidity85%💦 very humid
Dew point13°C / 55°F
Sunshine9.2 h/day
Daylight13.3 h
Wind5 km/h / 3 mph
Air quality (US AQI)76🙂 moderate

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Alishan in May

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Shoulder seasonschool holidays in 2 of the markets that fill it, an ordinary month(estimated)

JFMAMJJASOND

Peak crowdsBusyShoulder seasonQuiet

Best months for Alishan's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherAlishan's best weather comes in February, November and December — separate windows, not one continuous season.

JFMAMJJASOND

Best weatherFair weatherToughest weather

What's on in Alishan in May

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Nature

    Firefly season

    10 Apr – 15 May · usuallyFireflies

    Alishan holds about a third of Taiwan's fireflies and the peak is a few weeks from mid-April. It is a night walk at 2,000 m, so around 8°C once the light goes. Source ↗

  • Season

    Wet season

    MonsoonRisk

    28 rainy days and about 310 mm in the month — the real kind of rainy season, not afternoon showers.

    from the climate normals

What's on around the world in May →

Nearby, and something's on

Within 300 km of Alishan — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Alishan?

Loading map…

Alishan in May — FAQ

Is May a good time to visit Alishan?
May in Alishan: nice, soaked, with muggy air — fine if you can take 28 rainy days. It ranks #9 of 12 months for Alishan on SeasonMap's comfort score (70/100).
What is the weather like in Alishan in May?
In May, Alishan averages a daily high of 18.8°C and a low of 12.3°C, with about 309.8 mm of rain over roughly 27.8 rainy days.
What is the air quality in Alishan in May?
Alishan has a mean US Air Quality Index of about 76 in May.

Within 300 km: Sun Moon Lake's Firefly season around 1 Apr – 15 May, and Kenting's Calm sea season around 1 Apr – 30 Sep.