The extreme heat standard means the temperature is equal to or exceeds 38 degrees. When it is hot, the temperature is 35-37 degrees. When it is muggy, the temperature is 28-35 degrees.

Sultriness, muggy weather refers to high temperature and high humidity weather that makes people feel hot flashes and stuffy. Occurs under cloudy and windless conditions.

Standards for hot and muggy weather vary with seasons, labor intensity, and regions. Generally, one of the following pairs of temperature and humidity values ​​is used as the lower limit standard for muggy weather: (l) temperature 35°C, relative humidity 25%; (2) temperature 30°C, relative humidity 40%; (3) temperature 25°C, relative humidity Humidity 65%. The higher temperature value is used as the standard in summer, and the relatively lower temperature value is used as the standard in cool season.