Climatic characteristics of Beijing

The climate in Beijing is characterized by four distinct seasons. It is dry in spring, hot and rainy in summer, refreshing in autumn and cold and dry in winter. The wind direction has obvious seasonal variation, with northwest wind prevailing in winter and southeast wind prevailing in summer. The climatic characteristics of the four seasons are as follows:

Spring: the temperature rises rapidly, the temperature difference between day and night is large, and it is dry and windy. With the gradual increase of the sun's altitude angle, the days in spring become longer, and the heat obtained from the ground exceeds the expenditure, so the temperature rises rapidly. The monthly average temperature rises by 9-6℃, the average temperature in March is 4.5℃, and the average temperature in April is 13. 1℃. The daytime temperature is high, the nighttime radiation cooling is strong, and the temperature is low, which is the season with the largest temperature difference between day and night. The average daily temperature is 4 degrees. The maximum daily temperature difference is 16.8℃. In addition, cold air activities are still very frequent in spring. Due to the sudden drop in temperature, "late spring cold" weather is easy to form late frost. There are many strong winds, and the number of windy days above Grade 8 accounts for 40% of the total number of days in the whole year. When strong winds appear, they are often accompanied by floating dust, sand blowing and sandstorm weather. Less precipitation in spring aggravates the spring drought, so it is called "spring drought in September of ten years"

Summer: it is extremely hot and the precipitation is concentrated, forming the same season of rain and heat. Except in mountainous areas, the average summer temperature in plain areas is above 24℃. Although the hottest month is not June, the extreme maximum temperature mostly appears in June. July enters the midsummer, which is the hottest month of the year. The average temperature is close to 26℃, the high temperature is stable and the temperature difference between day and night is small. Summer precipitation accounts for 70% of the annual precipitation, mostly in the form of heavy rain. Flooding in the plain is one of the main natural disasters in Beijing in summer. In addition, the strong thermal convection in mountainous areas has led to thunderstorms in some areas, accompanied by hail, which has caused certain losses to agriculture.

Autumn: The weather is crisp, warm and cold, and sunny. After autumn, the cold air in the north began to invade and the temperature dropped rapidly. Therefore, the early arrival of the first frost often happens.

Winter: the cold is long. Winter lasts for five months, and if the average temperature is below 0℃, it lasts for three months (65438+2-2 months). In the dead of winter, the average temperature in the plain area is below -4℃, the average temperature in the mountainous area is below -8℃, and the extreme minimum temperature in the plain area is -27.4℃. Winter precipitation accounts for 2% of the annual precipitation, and there is often no precipitation (snow) for more than a month.