Onset/cessation
| Ceiling | |
|---|---|
| 1 | < 200 ft |
| 2 | 200 – 400 feet |
| 3 | 500 – 900 feet |
| 4 | 1000 – 1900 feet |
| 5 | 2000 – 3000 feet |
| 6 | 3100 – 6500 feet |
| 7 | 6600 – 12,000 feet |
| 8 | > 12,000 feet or unlimited ceiling |
| Visibility | |
|---|---|
| 1 | < ½ mi |
| 2 | ½ – 1 mi |
| 3 | 1 – < 2 mi |
| 4 | 2 – < 3 mi |
| 5 | 3 – 5 mi |
| 6 | 6 mi |
| 7 | > 6 mi |