What does Cold Dew mean?

Cold dew is the seventeenth solar term in the twenty-fourth solar term of the lunar calendar, belonging to the fifth solar term of autumn, indicating the official beginning of autumn season; When the sun reaches 195 degrees of longitude on October 8 or 9 of the Gregorian calendar every year, the temperature in most parts of southern China continues to drop, Nanling and the vast areas to the north have entered autumn, the northeast has entered late autumn, and the northwest has entered or is about to enter winter.

What does cold dew mean?

Cold dew means that the temperature is lower than white dew, the dew on the ground is colder, and it is about to condense into frost. In the cold dew season, the vast areas in the south and north have entered autumn, and the northeast and northwest regions have entered or are about to enter winter. In most years, the first frost has been visible in Beijing, the capital. Except for the Qinghai-Tibet Plateau, which snows all year round, snow has generally begun to fall in the northeast and northern parts of China.

Climatic Characteristics of Cold Dew

China traditionally regards dew as a sign of cooler weather. Mid-autumn white dew solar term "dew condensation and white", to the autumn cold dew is already "dew cold, will condense into frost". At this time, the temperature in most parts of southern China continues to drop. The daily average temperature in South China is less than 20℃. Even in the coastal areas of the Yangtze River, the mercury column is difficult to rise to above 30℃, while the lowest temperature can drop below 10℃. Except for a few valleys and lowlands in the northwest plateau, the average temperature in five days is generally lower than 10℃. According to the standard of climatology, it is winter, thousands of miles of frost spread, thousands of miles of snow drift, which is very different from the autumn color in South China.

Cold Dew and Agricultural Production

Rainfall in southern China during the cold dew period is also decreasing, mostly around 20 mm in the west of South China and 30 to 40 mm in the east. Continuous rain is very frequent, morning and evening, dark rain, affecting the "three autumn" production, becoming a disastrous weather in most areas of southern China. The climate characteristics accompanying the continuous rain are high humidity, more cloud cover, less sunshine, more cloudy days, and a significant increase in foggy days since then. However, whether the autumn rain is serious or not directly affects the progress and quality of "Sanqiu." To this end, on the one hand, we should use weather forecasts to seize sunny days for harvesting and sowing. On the other hand, it is necessary to adopt various effective farming measures such as deep ditch and high compartment to reduce moisture damage and improve sowing quality according to local conditions. In plateau areas, snow damage is most serious before and after cold dew, snow blocks traffic and endangers animal husbandry production, so attention should be paid to prevention.