Global climate change increased air temperature variability and enhanced the frequency and intensity of extreme weather events, such as heat waves and cold spells with adverse impacts on public health. In this study, we examined the relationships of the daily air temperature with mortality in Shanghai in 2003, a record hot year. We found V-shaped associations between cause-specific mortality and daily air temperature. The temperature-mortality relationship well manifests in three temperature measures, but with varied temperature thresholds for different age groups and mortality categories. Two heat waves and one cold spell were identified in 2003 and brought out excess mortality. The first heat wave lasting for 19 days had a significant impact on total non-accidental, cardiovascular and respiratory deaths compared to the corresponding reference period. The second heat wave lasting for 14 days have resulted in excess mortality in three categories of mortality but without statistical significance. The cold spell lasting for 7 days only had a significant impact on total non-accidental and cardiovascular mortality. We also found the elderly are more sensitive to temperature variation. Our results suggest that air temperature is a significant factor influencing human mortality, particularly for the elderly.