Abstract: The variation trend of the diurnal temperature range (DTR) and its impacting factors were analyzed using methods of a liner trend and a statistic correlation analysis based on temperature data at 7 weather stations from 1961 to 2008 in Altay region. The results indicated that the seasonal DTR is in a significant decreasing trend, especially in winter. Variation of autumn DTR is small. The increasing trends of seasonal minimum temperature are the most significant, while those of seasonal maximum temperature are not significant. The monthly mean DTR has significantly positive correlation with sunshine duration, while it has negative correlation with total cloud cover, precipitation and vapor pressure. Annual DTR has significant correlation with precipitation and vapor pressure.

Key words: Diurnal temperature range (DTR), Linear trend method, Causing factor, Diurnal temperature range (DTR), Trend test, Impacting factor