Yibin climate

Yibin city belongs to subtropical humid monsoon climate, and the low mountains, hills and valleys have the climate attribute of south subtropical zone. It has the characteristics of mild climate, abundant heat, abundant rainfall, suitable illumination, long frost-free period, warm winter and early spring, and distinct four seasons. The annual average temperature is about 18℃, and the annual average precipitation is 1, 050- 1, 618 mm. May to 10 is the rainy season, and the precipitation accounts for 8 1.7% of the whole year. The main flood season is from July to September, and the rainfall is relatively concentrated. The annual average sunshine 1000~ 1 130 hours, and the frost-free period is 334~360 days. The annual average wind speed is only 1.23m/s, mostly northwest wind and northeast wind. The static wind frequency is relatively high, reaching 34-53%, and the wind speed is small.

Yibin has a total soil area of1073,300 hectares, accounting for 80.5% of the city's total land area. There are six types of soil in the city: purple soil, paddy soil, yellow soil, Huangshi lime soil, yellow brown soil and newly accumulated soil. In addition to the original vegetation in Laojun Mountain in Pingshan County, Xianfeng Mountain in Xingwen County and Daxue Mountain in Junlian County, most of the vegetation in the city is secondary vegetation and artificial vegetation after the original vegetation is destroyed. Subtropical secondary evergreen coniferous forest vegetation is widely distributed in China, and bamboo forest is a major feature. In 2004, the city's forest coverage rate was 37% and the green coverage rate was 45.6%.

Yibin's water system is an outflow water system, with the Yangtze River as the main vein, many rivers, high density and abundant water. The Jinsha River and Minjiang River meet to form the Yangtze River, which runs across the northern part of the city. There are more than 600 large and small rivers as tributaries of the Three Rivers. Nine medium-sized rivers, such as Wenxing River, Nanguanghe River, Changning River, Hengjiang River, Xining River, Huangshahe River, Yuexi River, Jianban River and ancient Song He, have basin areas of over 500 square kilometers. Another 2 1 river basin area 100 square kilometers to 500 square kilometers, and 23 small rivers basin area 50 square kilometers to 100 square kilometers. The tributaries and streams of the Three Rivers are distributed in an asymmetric river network from north to south or from south to north. Most of the tributaries in the south originate from high mountains, so the beach is full of water. The northern tributaries frequently flow through hills, with gentle water potential and wide shore potential. Major rivers: Minjiang River, River Verdon, Wenxing River, Nanguang River, Changning River, Hengjiang River, Xining River, Huangshahe River, Yuexi River, Jianban River, Jinsha River, Yangtze River and Yu He.