Taiwan has a subtropical monsoon climate, with wet, humid summers and short, relatively mild winters (though it often snows on the highest peaks). The north tends to be several degrees colder, and a lot wetter, than the tropical south. The northeast monsoon lasts about six months from October to late March and brings wet weather to Keelung and the northeast side of the island, while central and southern regions stay relatively dry. The southwest monsoon starts in May and ends in late September, primarily affecting the south. The latter part of this monsoon season is associated with typhoons that batter the east coast and central mountain range, with an average of two to three direct hits a year. That’s not the end of the rain, however – the annual “plum rain” season can bring two months of rain any time between early spring and early summer, affecting the whole island.
In winter, the average monthly temperature ranges from 15 to 20°C across the island, while mid-30s are common in the summer. Temperatures in the high mountains can be substantially lower than on the plains. In general, autumn and winter are the best times to visit, though early summer (May to July) can also be pleasant at higher elevations and in the north, and the high temperatures in midsummer make watersports and beaches far more tempting at this time.