風速が毎秒0.3メートル未満のとき、風は静穏と記録される。
When the wind speed is under 0.3 meters per second, the wind is recorded as calm.
今朝の観測では風は静穏だった。
In this morning's observation, the wind was calm.
煙がまっすぐに昇るのは静穏のしるしだ。
Smoke rising straight up is a sign of calm conditions.