Thua Thien Hue province is affected by both winter and summer wind in South East Asian region. Therefore, local wind significantly changes over seasons. Northern Truong Son range together with north east and south west wind form a right angle. Besides, Bach Ma - Hai Van range’s geographical position changes the direction of not only the dominant wind, but also the speed of wind blowing through deltas, valleys and mountainous areas. As a consequence, there is high frequency of calm wind (28 - 61%) and low average wind speed.
In the winter (from October to April), wind in the coastal delta mainly blows from the west to the north with the frequency of 25 - 29%. Later, north east wind reaches the frequency of 10 -15%. As Nam Dong valley is surrounded by mountains, south east wind accounts for 14 - 20% while northwest wind makes 10 -20%. In A Luoi, north east wind reaches the frequency of 30 - 44%.
In the summer (from May to September), the southern wind makes up 10 -16% while south west and north east wind is 11 - 14% and 10 - 16% respectively. In Nam Dong district, the south east wind accounts for 21 - 38% while northwest wind accounts for 10 - 16%. The most common wind in A Luoi district is northwest wind which makes up 34 - 36% in mid-summer (from June to August).
Very high frequency of calm wind is recorded in continental areas. In details, the data is 32 - 40% in coastal delta and 28 - 61% in mountainous areas. Calm wind frequency has a significant influence on air's self clearance, especially in valleys.
Monthly wind speed rarely changes over seasons, ranging from 1,0 to 8,6m/s. Yearly maximum wind speed recorded is 2,3m/s in A Luoi, 1,8m/s in coastal delta and 1,4m/s in Nam Dong valley. In spite of rather low monthly and yearly average wind speed, strong winds blowing from various directions are still observed in storm, tornado, north east wind or south west wind.
According to Thua Thien Hue Geography - Nature chapter
(Social Science Publishing House - 2005)