We record cloud cover by estimating the fraction of the sky that would be covered if all the clouds were pushed together.
Understanding Cloud Cover Measurement
The process of recording cloud cover involves a two-step thought experiment:
- Consolidate the Clouds: Imagine all the clouds in the sky were moved together.
- Estimate Sky Coverage: Determine how much of the sky would be covered by this consolidated cloud mass.
Cloud amount is measured in eighths of the sky obscured by clouds. This means:
- 0/8 represents a completely clear sky.
- 8/8 represents a sky completely covered by clouds.
Measuring Cloud Cover: A Practical Approach
Here's how to practically record cloud cover:
- Observe the Sky: Look up and take in the overall cloud distribution.
- Mentally Combine Clouds: Visualize all the clouds as if they were one contiguous mass.
- Estimate Coverage: Estimate what fraction of the sky this consolidated mass would cover.
- For example, if you think the cloud mass would cover approximately half the sky, record 4/8.
Common Cloud Cover Measurements
| Cloud Cover (Eighths) | Description |
|---|---|
| 0/8 | Clear sky |
| 1/8 | Few clouds |
| 2/8 | Scattered clouds |
| 3/8 | Scattered clouds |
| 4/8 | Partly cloudy |
| 5/8 | Mostly cloudy |
| 6/8 | Mostly cloudy |
| 7/8 | Overcast, but with breaks |
| 8/8 | Overcast |
Key Considerations
- Consistent Observation: Ensure the observer views the sky from the same viewpoint each time.
- Estimation is Key: Since we're estimating, there may be slight variations between observers.
- Training and Experience: Experience and training can improve accuracy in estimating cloud coverage.
This method of recording cloud cover allows for consistent and comparable weather observations. By using a scale of eighths, we can effectively quantify the amount of cloud present in the sky.
