Based on the mean air temperature,mean wind speed,precipitation,cloud cover and visibility data at Shengyang and Xinchengzi stations at 02:00,08:00,14:00 and 20:00 BST from 1992 to 2008,the effect of urban heat island (UHI) was analyzed under different weather conditions.Results show that UHI intensity in Shenyang region is the lowest at 08:00 BST under light and heavy fog conditions,while it is the highest at 20:00 BST and the lowest at 14:00 BST under other weather conditions.UHI intensity is higher in night than in daytime under different weather conditions.Difference of UHI intensity between nighttime and daytime is the largest under the clear and calm wind condition,with the value of 073 ℃.Under the light fog condition,UHI intensity is the strongest in autumn,but under other weather conditions,it is the strongest in winter.Under the heavy rain condition,UHI intensity is the lowest in spring,and under the other precipitation conditions,it is the lowest in summer.UHI intensity decreases with the precipitation increase,wind speed increases,and visibility decrease.The UHI intensity difference (UHI20:00-UHI02:00) is larger in night than that (UHI08:00-UHI14:00) in daytime under the condition from the first to third wind levels,and the rule is contrary under the other wind levels.There are not obvious rules under other weather conditions.