無論就預防風災或就工程設計而言，一地可能發生的最大風速都是不可或缺的重要數據。而站在天氣預報的立場，何種氣象因素會引起該等強風，亦必須有所瞭解。本文之目的即利用民國48至72年共25年台灣北部地區的觀測資料，分析強風（桓常風≥20kts；陣風≥30kts）的成因，並根據各類強風歷年所發生過的最大值，利用Gumbel的或然率法推估百年複現期的可能最大風速。
In this paper 25 (1948-1982) years data of wind vectors of Hsinchu and Taoyuan are analyzed. The work includes: (1) to find out and summarize the strong wind (mean wind speed ≥ 20 kts and /or gust speed ≥ 30 kts) in a synoptic point of view; (2) to estimate the possible extreme wind speed in the considered region through Gumbel's first asymptotic distribution model. The result shows that (1) Typhoon and monsoon are the major sources of strong wind; typhoon gives rise the strongest wind and monsoon contributes the most number of strong wind event. (2) The 100-year return period extreme wind speed in the considered region, with a 95.5% confidence level, may be as high as 160 kts for typhoon's strong wind; that for monsoon's strong wind is about 70 kts.
