The Start of Summer is the eleventh solar term in the 24 solar terms. It marks the end of the 6th lunar month and the beginning of the 7th lunar month. The solar term is determined by the position of the sun in the zodiac, reaching 105 degrees and occurring between July 6th and 8th of the Gregorian calendar. "Hot" is the meaning of "shu", and Start of Summer represents mild heat， not extremely hot. Although Start of Summer is not the hottest season of the year， it is immediately followed by the hottest solar term， Great Heat (da shu)， with the saying in folk culture， "Start of Summer and Great Heat， steaming above and boiling below." Many regions in China enter the period with the most thunderstorms starting from Start of Summer. 
As the Start of Summer approaches, the hottest days of the year begin. The term "Heat in the Triad of Summer" refers to the period of extremely high temperatures during the hottest days of the year. The Triad of Summer usually occurs between the Start of Summer and the Autumnal Equinox, and it is the period with the highest temperatures and the most humid and oppressive conditions throughout the year. The monsoon climate is the main characteristic of China's climate. During summer, influenced by the warm and humid air currents from the ocean, many areas in China experience high temperatures, humidity, and frequent rainfall. Although the Start of Summer is marked by intense sunlight, high humidity, and frequent rainfall, for crops, the concurrent occurrence of heat and rainfall is beneficial for their growth. 
In the past, in the southern regions of China, there was a custom called "Feast on New Crops" during the Start of Summer. After the Start of Summer, people would taste the new rice. Farmers would grind the freshly harvested rice into flour and make a meal to offer sacrifices to the gods of grains and ancestors. Then everyone would enjoy the new wine and other delicacies. In the northern regions, there was a tradition of eating dumplings during the Beginning of Autumn. During the Heat of the Year, people often had poor appetite and tended to be thinner than usual. It was said that this was the "harsh summer". And dumplings were considered appetizing and satisfying food in traditional customs. Moreover, the shape of dumplings resembles a treasure box, symbolizing "treasure hidden within", and eating dumplings was regarded as a symbol of abundant good fortune.

Historical Origin 
The Twenty-Four Solar Terms are specific festivals in the Chinese calendar that represent the natural rhythm changes and determine the "twelve months' names". They can accurately reflect the natural rhythm changes and contain profound cultural connotations and historical accumulation. The "Explanation of the 72 Solar Terms" compiled by the Yuan Dynasty scholar Wu Cheng: "In June, the festival... Heat, meaning hotness. It is divided into large and small parts. At the beginning of the month it is small, in the middle of the month it is large. Now the heat is still small." Heat indicates the meaning of being hot. Ancient people believed that during the period of the small heat, it was not the hottest time of the year, so it was called the small heat. The solar term rhyme goes: "The small heat is not very hot, the great heat is during the three hottest months." It indicates that the hottest period of the year has arrived, but it has not reached the extreme heat level. 
The term "小暑" means "minor heat", indicating that although one can already feel the heat at this time, it has not reached the hottest point of the year. Small Heat merely marks the beginning of the scorching summer. As an old saying goes： "The heat is most intense during the Summer Solstice." The Summer Solstice occurs between Small Heat and Summer Equinox， and it is the period with the highest temperature and the most humid and oppressive weather throughout the year. The monsoon climate is the main characteristic of the Chinese climate， which is a blend of continental and maritime climates. During summer， influenced by the warm and humid air from the ocean， it is hot， humid and rainy. The high temperature and abundant rainfall periods of the monsoon climate are basically the same， with rain and heat occurring simultaneously， which is conducive to the growth of crops. During the Small Heat season， the weather is hot， thunderstorms are frequent， and it is a time when all things grow vigorously. 
Weather changes 
During the Small Heat Festival, the duration of sunlight in the Northern Hemisphere gradually shortens. But why do the temperatures in most parts of China continue to rise steadily? This is because although the direct path of the sun is moving southward, it still shines directly on the Northern Hemisphere. The heat in the Northern Hemisphere still exceeds the demand, so the temperature will continue to rise during this period. The average temperature in the southern regions during the Small Heat Festival is around 26℃. In mid-July, in the low-altitude river valleys of southern China, the daily average temperature can exceed 30℃ and the daily maximum temperature can exceed 35℃. In the northern part of the northwest plateau, frost and snow can still be seen, which is similar to the scene in early spring in southern China. 
As the Start of Small Heat approaches the beginning of the Summer Heat period, the air humidity increases after the "Start of the Heat" arrives. The reason for the high humidity during the three hottest days of the year is that the southeast wind blows during this period, and the southeast direction is the Pacific Ocean and the Indian Ocean. The humid air from these oceans and the humid sea breeze result in high humidity during the three hottest days. The "high temperature and high humidity" is a climatic characteristic of southern China during the three hottest days, while in the northern regions, it is "high temperature and dryness". Small Heat is a mild heat, not extremely hot. It is not until Great Heat that it becomes the hottest time of the year. After the Small Heat period, there is rarely any cool wind on the ground, and the wind blowing also carries heat waves. The monsoon climate is the main feature of the Chinese climate. During summer, influenced by the warm and humid air currents from the ocean, many places in China experience high temperatures, humidity, and heavy rainfall. In southern China, the thunderstorm season also begins, often accompanied by strong winds and heavy rain. Tropical cyclones are frequent, and the number of tropical cyclones landing in China is increasing. In summary, the climatic characteristics of the Small Heat period are hot weather and an increase in thunderstorms. 
After the start of the Small Heat Festival, the regions of South China, Southwest China, and the Qinghai-Tibet Plateau are under the influence of the southwest monsoon from the Indian Ocean and the South China Sea; while the middle and lower reaches of the Yangtze River are generally under the control of the subtropical high pressure, experiencing high temperatures and little rainfall. In some years, the cold air from the north is still quite strong before and after the Small Heat Festival. In the middle and lower reaches of the Yangtze River, it is evenly matched with the warm air from the south, resulting in frontal thunderstorms. The thunderstorms during the Small Heat Festival are often weather indicators for the onset of the late summer rain, suggesting that the rain belt will remain in the middle and lower reaches of the Yangtze River for some time. 
During the Small Heat Festival, the northern regions of China have not yet entered the rainy season. China has a typical monsoon climate, and the rainfall areas are mainly controlled by atmospheric circulation systems such as the subtropical high pressure in the northwest Pacific Ocean. From mid-June to early July, the main rain belt in eastern China generally moves northward from the south China region, Jiangnan area, to the middle and lower reaches of the Yangtze River or the Huaihai region. Starting from the second half of July, with the seasonal northward movement of the subtropical high and other atmospheric circulation systems, the southwest monsoon will also advance northward. The southwest winds around the subtropical high will transport warm and humid air from the tropics and subtropics to the northern regions. This warm and humid air meets the cold air from the mid-latitudes in North China and Northeast China, and it is only then that the rainy season begins in North China and Northeast China. Every year from late July to early August, which is also known as "July Below and August Above", is the rainy season in North China, Northeast China and other northern regions of China. 
Phenological phenomena 
The Yuan Dynasty scholar Wu Cheng compiled the book "Explanation of the 72 Solar Terms". Based on the natural scenes around the Yellow River Basin and the characteristics of the 24 solar terms, he divided the 24 solar terms of the year into "72 periods", and each period was further divided into three phases. For the third solar term of Xiaoshu (Summer Heat), the three phases were: "The first phase: Warm wind arrives; the second phase: Crickets stay indoors; the third phase: Eagles become fierce." 
During the Small Heat Festival, there is no longer any cool breeze on the earth; instead, all the winds carry heat waves. The lines in "The Book of Songs - July" describing crickets are: "In July, they are in the fields; in August, they are in the rooms; in September, they are in the doors; in October, the crickets enter under my bed." The month mentioned in this text, August, is the sixth month of the Chinese lunar calendar, which is the time of the Small Heat Festival. Due to the heat, the crickets leave the fields and go to the corner of the courtyard to escape the heat. During this festival, eagles move in the cool high altitude because the ground temperature is too high. 
Agricultural activities 
Water storage for drought prevention 
During the Small Heat period, the western part of South China experiences the most frequent rainfall. The number of rainy days in July and August each year can account for over 75% of the total annual rainfall, usually lasting for about 3 days. However, in the eastern part of South China, after the Small Heat period, due to frequent control by the subtropical high pressure, there are often consecutive sunny and hot weather conditions, and the area begins to enter the drought period. The climate characteristics of most areas in southern China, such as alternating drought and floods from the east to the west, have a significant impact on agricultural production. Therefore, it is necessary to take early measures to prevent drought and floods, and minimize the damage. The areas of South China, Southwest China, and the Qinghai-Tibet Plateau are located in the southwest monsoon rainy season brought by the Indian Ocean and the South China Sea; while the middle and lower reaches of the Yangtze River are generally under the control of the subtropical high pressure, experiencing hot and less rainy weather. The frequent occurrence of the summer drought has a great impact on agricultural production. It is particularly important to store water and prevent drought in advance at this time. 
Crop Management 
Around the time of the Start of Summer, except for the northeastern and northwestern regions where winter and spring wheat and other crops are being harvested, agricultural production mainly focuses on field management. 
The early rice is in the late stage of grain filling. Early-maturing varieties will mature and be harvested before the Great Heat Festival. It is necessary to maintain a dry and wet condition in the field. 
The rice plants have begun to stretch their stems and have entered the booting stage. At this point, it is necessary to apply additional fertilizer for the grains to promote larger grains and more yield. 
The single-season late rice is currently in the stage of tillering. It is necessary to apply the tillering fertilizer as early as possible. For the double-season rice seedlings, pest control should be carried out. The pre-planting fertilizer should be applied 5 to 7 days before transplanting. 
The hot summer period is when various pests such as aphids and red spiders thrive. Timely control of pests and diseases is another crucial aspect of field management. 
During the period of the Start of Summer, early rice and spring corn are in the filling and ripening stage, which is a crucial period for seed formation. Agricultural activities aim to prevent premature aging, promote filling, and increase the thousand-grain weight. In production, it is necessary to prevent heat-induced ripening and drought disasters. When encountering temperatures above 35℃ or drought conditions, irrigation measures can be taken to improve the microclimate in the fields, or foliar fertilizers can be sprayed to enhance the crop's stress resistance. 
The rice and summer corn are in the transition period from vegetative growth to reproductive growth, during which they require a large amount of water. If the water supply is cut off prematurely in the rice fields, it will be detrimental to the formation of effective tillers and the differentiation of young ears. Summer corn may suffer from water stress at the stem elongation stage, leading to significant yield reduction. Cotton is in the boll-forming stage, and late rice is in the seedling stage. It is necessary to ensure that the ditches are unobstructed to prevent waterlogging. In addition, during the Xiaoshu period, the weather conditions are favorable, making it an opportune time for conducting field operations such as pest and disease control. 
Around the time of the Start of Summer, most areas in southern China enter the season with the most thunderstorms. Thunderstorms are a severe weather phenomenon that often occurs along with strong winds, heavy rain, and sometimes hail, and can cause disasters. In the eastern part of South China, after the Start of Summer, due to being frequently controlled by the subtropical high pressure, there are often consecutive hot and dry weather conditions, and the period of drought begins. The climate characteristic of southern China is alternating drought and floods in different regions.