Abstract: The 10-layer air temperature data collected from five 100-meter-high meteorological towers in Urumqi City, Xinjiang, China were used to analyze the characteristics of the seasonal variation and diurnal variation of the air temperature of Urumqi City and its suburbs and to construct the air temperature profile. The results show that in Urumqi, there are obvious temperature inversions in all seasons, especially in the northern suburbs. In the surface layer with the height of 100 m the diurnal temperature range is small (from 3.5 to 5.5 ℃) in the main urban area, while is relatively large (from 4.2 to 7.0 ℃) in the suburbs. In summer, the air temperature is higher in the suburbs than that in the urban. While in winter, the temperature is the lowest in the northern suburbs, but the highest in the southern suburbs. In the daytime, the atmosphere shows basically a super-adiabatic instability. The air temperature in the urban area is higher than that of the suburbs at night. In spring and autumn, the air temperature difference between urban and suburb is big at night (but small in the day time).The closer it is to the ground, the bigger the difference is. The temperature between the urban area and the south suburb is 2.4 ℃ in spring, and 3 ℃ in and autumn. The highest temperature and lowest air temperature did not achieve simultaneously in all seasons in the urban area and in the rural areas. The highest temperature appears in the period from 17:00 PM to 18:10 PM, from 16:00 PM to 17:20 PM, from 14:30 PM to 15:50 PM (it lags 1.5 hours in north suburbs), and from 17:00 PM to 18:00 PM (it appears ahead of 1.5 hours in south suburbs) in summer, autumn, winter and spring respectively. The minimum value of air temperature appears in the period from 7:10 AM to 8:20 AM, from 8:00 AM to 9:00 AM, multiple time periods, and from 7:30 AM to 8:40 AM in summer, autumn, winter and spring respectively.

Key words: boundary layer')">boundary layer, air temperature, profile, Urumqi City