农谚讲:“清明断雪,谷雨断霜”,意思是说在四月中下旬往往还会出现“霜”,对早稻、棉花、蔬菜的秧苗威胁甚大,有时会造成大批死亡。因此,掌握霜的先兆,及时采取防御措施,是相当必要的。当气温在5℃以下,晚上明星亮月,微吹西北、北、西风或西风偏南,半夜后寒冷刺骨,就会落霜。特别要警惕后春“冷尾暖头”雨绵绵,忽儿微吹西北风,寒气逼人,半 The saying goes: “Ching Ming off snow, Gu Yu off frost,” meaning that in mid-to-late often there will be “frost” on the early rice, cotton, vegetable seedlings threatened, and sometimes cause a large number of deaths. Therefore, it is quite necessary to grasp the precursor of frost and take timely defensive measures. When the temperature is below 5 ℃, the night star bright moon, slightly blowing the northwest, north, westerly or westerly south, cold night after biting, it will fall cream. In particular, be wary of the spring after the “cold end warm head” rain spontaneously, suddenly micro blowing northwest wind, cold pressing, half