The Tropic of Cancer crosses Taiwan almost 100 km south of Shei-Pa National Park, which therefore lies entirely in the subtropics. Temperatures, however, vary a great deal according to the altitude. The range of altitudes in the park is from 760 meters above sea level in the Da-an River Valley to 3,886 meters at the top of Syue Mountain; average temperatures to be expected during the year are as follows:

Altitude 1,000 meters in January 9℃
July 22℃
2,000 meters January 5℃
July 16℃

Precipitation is heavy: the park has an average annual rainfall of between 1,500 and 3,000 mm, the rainy season being from May when spring monsoons bring the heavy "plumrains," to October, by which the typhoons are usually over. There is also heavy precipitation in winter, with the higher peaks receiving it in the form of snow.

The northeast-southwest Syue Mountain Range divides the park into two different climatic regions: the land to the north of the range has Taiwan northwest mountain climate, with monsoon winds and typhoons causing heavy rainfall. The region to the south of the range has the climate of western slopes of the Central Mountains, with marked variations in rainfall.