This paper uses the temperature data of 9 observation sites in the Pearl River Delta region from 1959 to 2012 (June-August) at 02h, 08h, 14h and 20h, and studies the temporal and spatial distribution characteristics of summer hot and cold weather days and intensity in the Pearl River Delta region, as well as warm nights. The trend of the number of days has been analyzed over the years, and the impact of the urban heat island effect of Guangzhou in the summer of 2000-2012 on the hot and cold weather is analyzed. The research shows that: 1) The spatial and temporal distribution characteristics of the number and intensity of high temperature heat waves in the Pearl River Delta region are similar, and the spatial distribution decreases from north to south. The time distribution decreases from the 1960s to the 1980s, and the trend begins to increase in the 1980s. After the 21st century, it increased sharply and reached its peak in 2007. 2) The number of warm night days in the Pearl River Delta region showed an increasing trend, and the distribution of high-valued areas was similar to the distribution of high-temperature heat waves and intensity, which occurred after the late 1990s; 3) In the summer of 1980-2012, the increase rate of various elements in Guangzhou Station was the fastest, indicating that the urban heat island effect enhanced the intensity and duration of the high temperature heat wave (warm night) in Guangzhou; 4) Summer 2000-2012 During the 6 high-temperature heat waves in Guangzhou, the number of warm night days in the city accounted for 78.6% of the total number of days, and the number of warm night days in the suburbs accounted for 14.2% of the total number of days, indicating that the effect of urban heat island effect on nighttime temperature during urban heat wave is more prominent than during the day.