Clouds are by default at the normal cloud height - these are normally too far above the player to generate when the player is at ground level, but can be seen when climbing a mountain in mapgen v5 or v7.
Spoiler
https://github.com/Qwertymine/craft_clo ... master.zip
Github
https://github.com/Qwertymine/craft_clouds
Depends - None
License - WTFPL