I don't understand the weather forecast of iphone. What does it mean that the weather forecast on Thursday is like an airstream?

It belongs to the fourth wind in Beaufort scale, with the wind speed of 3.4~5.4m/s, 12 ~ 19km/h ... The wind level is determined according to the wind speed above the ground 10 meter. Generally, it is expressed as 0 to12 * * 13, but in special circumstances, there is a wind level above13. Level 3 wind is called breeze, which is characterized by leaves and twigs shaking, flags unfurling and tall grass shaking.

Extended data:

Special symbols representing various weather phenomena, clouds and sky conditions. Includes weather phenomenon symbols for observation and recording and weather graphic symbols for media communication.

When observing a certain weather phenomenon, meteorological observers should record the corresponding symbols in the "Weather Phenomenon" column of the observation record book of the day, except for a few phenomena, and also record the starting and ending time. Based on these symbols, combined with the intensity, coexistence and some characteristics of weather phenomena, a group of symbols that can be filled in weather maps are called cartographic symbols.

References:

Weather symbol? Baidu baike