Time and Distribution of Glaze

Most of the glaze occurs in one month from early January to early February or the middle ten days of February, it starts early in north, late in south, early in mountainous areas and late on plains, while it ends in an opposite way.

The glazed frost comes earlier in higher mountainous areas and ends later. Take the Bright Summit of the Mount Huang in southern Anhui province, the glazed frost generally begins in early November and ended in April of the following year for 5 months.

According to statistics, the frequency of glazed frost in Yangtze-Huaihe river basin is once every 2 or 3 years in the Huaibei region along the Huaihe river and once every 7 or 8 years in the south of Huaihe river. In mountainous areas, however, there is a great difference between the valley and the mountain top. There is almost no glazed frost in some valleys in mountainous areas, while it occurs almost every year in high areas.

The glazed frost is common in mountain and lake areas. It appeared during the time from December to March in most areas of China. The average features of glazed frost a year in China are that there is more in the south and less in the north. But there is no hail or glazed frost in southern China because it is hardly close to 0℃ out of warmth in winter. There are more glazed frost in wet areas and few in dry areas (especially in high mountain areas where the glazed frost is the most).

The stations, where the average number of days of glazed frost is more than 20 to 30, are almost all in high mountainous areas. Whereas the average number of days of glazed frost of most stations in the plain area is below 5 days.

Most glazed frost commonly occurs during the warmer spring and autumn in the north where winter is very cold, such as the Tianchi meteorological station on Mount Changbai where glazed frost mostly happens in May with an average of 5.7 days. In September, glazed frost lasts 3.5 days on average there. During the winter, from December to March due to the low temperature glazed frost has never been seen.

While during winter in the south when it is colder, there is more glaze, such as the meteorological station on Mount Emei where there are up to 26.4 days with glaze on average in December, and as many as 24.6 days in January. In some years, glaze once occurred everyday in December, January and March.