The extreme heat standard is that the temperature is equal to or higher than 38 degrees, 35-37 degrees when it is hot, and 28-35 degrees when it is sultry.

Sultry weather) refers to hot and humid weather that makes people feel sultry. Occurred in cloudy and windless conditions.

The standard of sultry weather varies with season, labor intensity and region. Generally, the following pair of temperature and humidity values are taken as the lower limit standard of muggy weather: (l) the temperature is 35℃ and the relative humidity is 25%; (2) The temperature is 30℃ and the relative humidity is 40%; (3) The temperature is 25℃ and the relative humidity is 65%. In summer, the higher temperature value is the standard, and in cool season, the lower temperature value is the standard.