The seasons are divided and called differently due to the cold, warm climate and long and short day and night changes. We all know that the climate is warm spring and autumn, hot summers, and cold winters. If we divide a year into four seasons, the number of days in all seasons seems to be the same, just a day or two less; it doesn’t count whether there are short or long seasons. But because the world’s locations are different, some in the North, some in the south; some places are far from the sea; some places are near the sea; some are plain, some are high mountains. In some places, the wind usually blows from one direction; in other places, the wind usually blows from other directions; Some call Southeast wind, some we call Northeast wind. Therefore, in the same period, the climate in different places is also very different. For example, in January in Harbin, is white snow everywhere, but in Guangzhou, one can still see blooming flowers. Normally, we use high and low temperatures to define seasons according to each region’s actual climatic characteristics. In China, the most common way is to take each tail’s average temperature (five days is one tail). The demarcation temperature between cold and warm is 10 ° C and the boundary temperature between warm and hot is 22 ° C. Below 10 ° C is specified as winter, 10 ° C to 22 ° C is specified as spring and autumn, 22 ° C or more will be specified as summer. Based on that criterion to delineate the seasons, the short four seasons length of different regions will not be the same.
Spring in Northern China is quite short, usually less than two months. For example, spring in some places like Beijing starts from 1-5 April to 21-25 May, in Shenyang is from 21-25 April to 10¬14 June, in Harbin, from 26 -30 April to 20-24 June. You can see the weather in these areas, remove the heaters in winter, and quickly set up tents for summer.
The season’s determination is based on the temperature, so the rapid or slow increase or decrease in temperature will determine the long or short season. In the North of China, solar radiation is very weak; the lighting time is short. Also, there is often cold air flowing from the North; the temperature is very low. After the coldest period in January passed, on the one hand, due to the gradual stronger solar radiation, on the other hand, due to the constant weakening of cold air, the temperature gradually increased, the weather also gradually became warm. But the amount of rain this time is very little, making the air dry. By the end of March, the solar radiation continues to grow stronger, and the cold air continues to weaken, causing the temperature on the ground to rise rapidly. Therefore, the areas in the North are usually from March to April; the temperature amplitude increases the highest, the temperature in April increases significantly compared to March. For example, in March, the average temperature in Beijing was 4.4 ° C; at this time, the weather was still quite cold. In April, the average temperature was 13.2 ° C; at this time, it was spring, the weather was warm and pleasant.
During the spring, the amount of rainfall is not much, except for windy days; most of them are still sunny days with dry air, the solar radiation is continuously increasing, and the heat is absorbed above. The ground itself rose rapidly; the air temperature also increased dramatically. Spring has begun in the summer for less than two months. For example, the average temperature in May in Beijing reaches 20.2 ° C, and in June, it rises as high as 24.2 ° C. So spring in Beijing is usually quite short.
Likewise, after the hottest period in July passed, the solar radiation weakened again. The cold airflow was constantly increasing, so the temperature gradually decreased. The amplitude dropped to the lowest Is from October to November. For example, the average temperature in October in Beijing was 12.5 ° C and in November dropped to 4.0 ° C, now it was frozen.
In general, the main reason autumn and spring in northern China is so short is that the latitude is quite high, winter comes early, and it passes late. Therefore, winter in the Northern Hemisphere latitude regions is longer than the Southern Hemisphere latitude areas.