长沙地区是我省温洲密柑的主要产区之一。由于我国冬季多为极地大陆干冷气团所控制,盛行大陆西北季风,北方寒潮频频南下,加之长沙地区北临滨湖平原,冬季冷空气容易侵入,因此冬季的温度比邻省同纬度地区显著偏低,气候比较湿冷。长沙地区和浙江温洲地区都靠近北纬28°,但长沙12—2月的气温比温洲低2.5℃～3.6℃.(见表一) Changsha area is our province Wen Zhou citrus one of the main producing areas. Due to the fact that most of the winter in our country is controlled by the dry continental air mass of the polar continent, the northwest monsoon prevails in the north and the cold in the north frequently goes south. In addition, the plains near Binhu are located in the north of Changsha and the cold air in winter is easy to invade. Therefore, The climate is chilly. Both Changsha and Wenzhou are close to latitude 28 ° north latitude, but the temperature in Changsha from February to February is 2.5 ℃ -3.6 ℃ lower than that of Wenzhou (see Table 1)