Beijing has a warmest period of time from mid to late July in summer,7 with an average maximum temperature of 31. As incoming solar radiation reduces gradually starting from August, the air temperature also begins to decline, with a highest temperature below 30!aIn late summer, the average daily maximum temperature goes down gently. It comes down to 29°C in late August from 30°C in early August, wit a decline less than 2°C. Temperature goes down less gently in September,.. from 28°C in early September to 24!ain late September, with a drop of 4 However, the interannual variations of maximum temperature for the same day can be very large, from about 15°C in late summer to over 20°C i autumn. For example, the highest temperature can be 35°C, and the lowest 17°C on August 21, with a difference of 18°C. On September 15, the highes temperature is 32°C, and the lowest less than 9°C, with a difference between the two. The interannual variation of daily lowest 23 diurnal temperature is also large, though slightly smaller than the highest.
