Adjective : a windless summer afternoon.    From Dictionary.com. 

RAIN FELL slowly through windlessness, almost a mist.    From Wordnik.com.  [The Boat of a Million Years]

Heat lightning sometimes nickered yonder, and thunder muttered into windlessness.    From Wordnik.com.  [The Boat of a Million Years]

The factors in this expression are unseasonableness, not for dried leaves, but for prodigious numbers of dried leaves; direct fall, windlessness, month of April, and localization in France.    From Wordnik.com.  [The Book of the Damned] Reference

Likewise, also, in the case of objects widely divergent, the examination of likeness is useful for purposes of definition, e.g. the sameness of a calm at sea, and windlessness in the air (each being a form of rest), and of a point on a line and the unit in number-each being a starting point.    From Wordnik.com.  [Topics] Reference

When the agony of windlessness was gone and I could question him he assured me that the horses were well enough, but that he and his two companions were hungry.    From Wordnik.com.  [The Eye of Zeitoon] Reference

“windlessness” and “calm-on-the sea” as examples suggests that they were not the by-products of some other sort of investigation, e.g. cosmology, but were chosen precisely to illustrate principles of definition.    From Wordnik.com.  [Archytas] Reference

C: D’ (e.g. as knowledge stands to the object of knowledge, so is sensation related to the object of sensation), and ‘As A is in B, so is C in D’ (e.g. as sight is in the eye, so is reason in the soul, and as is a calm in the sea, so is windlessness in the air).    From Wordnik.com.  [Topics] Reference

The examples given are “windlessness”.    From Wordnik.com.  [Archytas] Reference