What's the weather like in Xichang in winter

First, it is warm in winter and cool in summer, and the four seasons are like spring.

Xichang is controlled by warm and humid monsoon in southwest and southeast in summer, with concentrated precipitation, not hot in midsummer, and cool and humid in summer and autumn. In winter, it is influenced by the polar continental air mass in half a year, and the high altitude is controlled by the dry and warm westerly airflow in the south branch. It is very warm in winter, forming a climate characteristic of "no severe cold in winter, no high temperature in spring, no intense heat in summer and cool in early autumn". There are many sunny days, with strong solar radiation during the day, the ground temperature rises sharply, the radiation in the clear sky is lost at night, the temperature drops rapidly, and the temperature difference between day and night is large. There is a saying that "there is no winter and summer in a year, and there are four seasons in a day". The temperature in annual range is small and the daily range is large. The annual average temperature range is only 13C, which is one of the areas with the smallest annual average temperature range in China.

Second, the rainfall is abundant and concentrated.

The rainfall in Xichang is concentrated, and 93% of the annual rainfall is concentrated in the summer half year. Night rain rate is high in rainy season, and the amount of night rain accounts for about 75% of the annual rainfall. During the day, the temperature in the mountainous area around the basin is low and the temperature rises slowly, and the air sinks, which is not conducive to water vapor condensation and less rain. The temperature in the basin rises rapidly in the afternoon, and the air around the basin rises along the hillside at night, which is conducive to the condensation of water vapor, so it is rainy. The Indian Ocean monsoon brings a lot of water vapor and forms unstable air stratification, which is prone to thunderstorms, often at night, and the rain clears up after dawn.

3. Sufficient sunshine and abundant light and heat resources.

Xichang is high in altitude, low in latitude, with large solar altitude angle, many sunny days, many sunshine hours, strong ultraviolet rays, high wind speed, large evaporation of water vapor, low humidity, few foggy days and good visibility. Its sunshine is the high-value center in the same latitude zone, and its accumulated temperature meets the needs of crop growth in four seasons. The ground temperature is higher than the air temperature, and the evaporation is greater than the precipitation. In winter and spring, the weather is crisp, sunny during the day and breezy at night, so it is called "Moon City".

Fourth, the four seasons are not obvious, and the dry and wet seasons are distinct.

Xichang 65438+February-March is the dry season, and June-September is the rainy season. In the dry season, the climate is dry, the temperature is high during the day and afternoon, the daily temperature difference is large, the sunshine time is long, and the ground wind is strong in the afternoon. The rainy season is characterized by concentrated precipitation, abundant rainfall, small daily temperature difference and continuous rain at night. In addition, in this season, air stratification is very unstable, convection is strong, and thunderstorms and hail are frequent. Due to the different monsoon intensity, advance and retreat time, precipitation is unevenly distributed in time and space, and it often suffers from natural disasters such as drought and flood.

Verb (abbreviation of verb) In the transitional season, the climate is changeable.

April-May in Xichang and 10- 1 1 are the seasons of air flow changes in winter and summer, which are called transition seasons. April-May is the transition from dry season to rainy season, which has both dry season climate characteristics and some rainy season climate characteristics. The solar altitude angle is increasing, the atmosphere receives more and more solar radiation, the warm air is gradually strengthened, the cold air is gradually weakened, the cold and warm air alternate frequently, and the weather is changeable. In April, the afternoon wind is still very strong. In May, due to the northward withdrawal of the upper-air jet, the southwest wind weakened obviously in the afternoon, and the upper-air circulation situation is changing to the rainy season. The atmosphere is often unstable, and cloud cover, thunderstorm, hail and rainfall increase. 10- 1 1 is the transition from rainy season to dry season. The basic climatic characteristics in rainy season gradually decrease, while those in dry season gradually increase. The airflow in the south branch is obviously strengthened and expanded southward, the scale of westerly ridge is obviously increased, the intensity of cold air is strengthened, the subtropical high is weakened and moved southward, the summer monsoon is weakened until it disappears, and the water vapor transport is obviously reduced.

Six, the mountain three-dimensional climate is obvious, and the climate types are diverse.

Xichang is located in the plateau, with prominent vertical belt and large height difference. The temperature decreases with the elevation. Every time the altitude rises 100 m, the temperature drops by about 0.6℃, the active accumulated temperature drops by 282℃, and the frost-free period decreases by 12 days. Alpine valleys in China can be roughly divided into six climatic zones according to different mountain slopes: 1200— 1300m is equivalent to tropical climate in South Asia; 1300— 1800 m is in the middle subtropical zone; 1800-2100 meters is north subtropical; 2 100-2500m is the south temperate zone; 2500-3000 meters is the middle temperate zone; Above 3000 meters is the north temperate zone. There is no summer in Luoji Mountain and Yak Peak, and there is no winter along Yalong River. Therefore, the climate of Xichang has three-dimensional climate characteristics: "the top of the mountain is cold, the mountainside is mild, and the valley is dry and hot" and "one mountain is divided into four seasons, and ten miles are different from the sky". The diversity of climate resources is beneficial to crop growth in different climatic zones.