Abstract: Based on the data of the daily mean and minimum temperature from 22 meteorological stations during the period of 1961-2007 in Xinjiang cotton area,the spatial distribution of beginning data of 10℃and the latest frost were analyzed.The results showed that the earliest beginning date of 10℃ and latest frost were in Turpan,followed by in southern Xinjiang,delayed from west to east in Tarim Basin,and latest in northern Xinjiang and Hami.There was significant linear correlation between the beginning data of 10℃ and the latest frost in the most of cotton's area.The latest frost period was earlier than the beginning data of 10℃ in the northern Xinjiang cotton area,Turpan cotton area and the most of southern Xinjiang cotton area.The latest frost period was after the beginning data of 10℃ only in Hami,Qiemo and Minfeng.Compared with the latest frost period,the change of beginning data of 10℃ was more stable in the northern and eastern Xinjiang cotton area,while the situation was the opposite in the southern Xinjiang cotton area.If the beginning data of 10℃ was taken as the index for the cotton's seeding date,the cotton could be at greater risk of frost in Hami cotton area.Therefore,the cotton's seeding time should be delayed 10 days after the beginning data of 10℃.There was definite risk in the south-eastern Tarim Basin cotton area.However,it was appropriate in the most of cotton area in Xinjiang and the cotton's seeding time was in the beginning or before the data of 10℃.The result was of great significance to get meteorological service indexes about cotton's seeding time and to improve the meteorological service of cotton.

Key words: Latest frost, Beginning date of 10℃, Spatial distribution characteristics, Cotton's seeding time