Assertion: wind | /r/HasProperty | calm
Facets:
Source sentences:
text: Stand-alone systems (systems not connected to the utility grid) require batteries to store excess power generated for use when the wind is calm.
text: The legend at the bottom of the wind rose gives additional information such as the unit (m/sec), the average wind speed for the month over all hours, the percentage of time that the winds are calm, and the years, months, and hours of data on which each rose was constructed.
text: Winds are calm.