Taipei's climate is subtropical and notably wet, with rain or drizzle possible at almost any time of year. The best months for visiting are October to early December, when the worst of the summer humidity is past, typhoon season is winding down, and temperatures sit in a pleasant 20-25°C range. March to May is the other good window — wet but mild, with the Yangmingshan cherry and calla-lily blossom peaking around late February.
Summer (June to September) is hot, humid, and frequently disrupted by typhoons, which can shut down the city for a day or two; the rains in June (the meiyu season) can last continuously for a week. Winter is cold by Taiwanese standards — 12-18°C, rainy and damp — but never freezing. Crowds at the major sights peak around Chinese New Year and the late-October Pride parade; otherwise Taipei is comfortable year-round.