Douglas Sea State Reference
Enter a significant wind-sea wave height in metres or feet to see its approximate Douglas class.
A QUICK WALKTHROUGH
How to use this tool
- Enter a significant wind-sea wave height in metres or feet to see its approximate Douglas class.
- Classify height
- This height-based reference approximates the wind-sea classes. A single wave can be higher. It does not classify swell, assess navigation risk, or indicate safety.
Douglas wind-sea bands
0: 0 m — Calm (glassy); 1: >0 to <0.1 m — Calm (rippled); 2: 0.1 to <0.5 m — Smooth; 3: 0.5 to <1.25 m — Slight; 4: 1.25 to <2.5 m — Moderate; 5: 2.5 to <4 m — Rough; 6: 4 to <6 m — Very rough; 7: 6 to <9 m — High; 8: 9 to 14 m — Very high; 9: >14 m — Phenomenal
Scope
This height-based reference approximates the wind-sea classes. A single wave can be higher. It does not classify swell, assess navigation risk, or indicate safety.
Source
Source: NOAA JetStream Max — Wind and Sea Scales; thresholds follow the Douglas sea-wave height bands. — [NOAA](https://www.noaa.gov/jetstream/ocean/waves/jetstream-max-wind-and-sea-scales)
GOOD TO KNOW
Common questions
Does the class include swell or navigation risk?
No. This tool classifies only the supplied wind-sea height band. It does not assess swell, individual-wave extremes, route conditions, or safety.