Abstract: In this paper, the climatic characteristics of the wire icing and the real-time weather conditions for wire icing occurrence are analyzed using the data of wire icing days from the establishment dates of the meteorological stations to 2010 and the data of daily, daily maximum and minimum temperatures, relative humidity and averaged daily wind speed during the period of 1961-2010, and the distribution of wire icing days is discussed. The results are as follows: (1) Wire icing occurred generally during the period from October to next April in the eastern part of northwest China in the forms of fog glaze mainly in the most northern region and Xi’an and glazed frost in the southwestern part; (2) Wire icing occurred often under the specific weather conditions: It occurred in the regions below 1 000 m. when the averaged daily temperature varied in a range of -5-4 ℃, daily minimum temperature in a range of -10-0 ℃, relative humidity was higher than 70%, and wind speed varied in a range of 0-1 m·s^-1; in the regions with elevation of 1 000-2 000 m, it occurred when the averaged daily temperature varied in a range of -15-4 ℃, daily minimum temperature in a range of -15-0 ℃, relative humidity was higher than 70%, and wind speed varied in a rrange of 0-4 m·s^-1; in the regions above 2 000 m, it occurred when the averaged daily temperature varied in a range of -15-0 ℃, daily minimum temperature in a range of -15--5 ℃, relative humidity was higher than 60%, and wind speed varied in a range of 0-8 m·s^-1; (3) Based on the climatic characteristics, the wire icing in the eastern part of northwest China occurred often in the west but rarely in the east, often in the regions with high altitudes but rarely in the regions with low altitudes. The potential occurrence of wire icing was high in the southwest and southeast, then in the northwest, central region and the region around the Huashan Mountain, and it was low in the east. In addition, the continuous wire icing occurred often in the regions with high occurring frequency of ice disasters.

Key words: wire icing, climatic characteristic, climatic division, icing periods, meteorological factor, northwest China