The answer above is very professional, let me tell you how to judge based on the things around you:
Zero-level smoke column rises straight into the sky,
First-level light smoke drifts with the wind
Level 2 light breeze blowing in the face
Level 3 leaf moving red flag display
Level 4 branches shaking flying paper
Level 5 leafy tree shaking< /p>
Level 6: It is difficult to walk with an umbrella
Level 7: It is difficult to walk in the wind
Level 8: branches are broken by winds at level 8
Level 9: tiles fly off the roof
Uprooting trees and knocking down houses at level 10
Levels 11 and 12 are rare on land