Abstract:  Based on the summer high temperature data from 1971 to 2010 in Wenzhou, the time sequence of high temperature process was built and the climate characters and the main weather systems were discussed. The results indicate that the temporal and spatial characteristics of summer high temperature are significant. The high temperature day increases suddenly since 2003, so is the frequency of hazard high temperature day. The main weather system influencing summer high temperature is subtropical high. When there is westely air flow, it is located near the ridge line of the subtropical high, there is warm center in the low level, and sunshine duration is long, the hazard high temperature will happen. When subtropical high reduces, it is southwesterly air flow in Wenzhou, it is controlled by warm area with above 20 ℃ at 850 hPa in south China, sunshine duration is long, high temperature weather occurs usually in Wenzhou. The above two weather types often appear from the last ten days of June to the first twenty days of July, and the probability is lower. The descending action caused by the north air flow outside the tropical system such as typhoon and so on will lead to high temperature weather, too.

Key words: Summer, High temperature, Climate characters, Formation reason