'Sunniness' definitions:

Definition of 'sunniness'

From: WordNet
noun
Lightness created by sunlight
noun
The quality of being cheerful and dispelling gloom; "flowers added a note of cheerfulness to the drab room" [syn: cheerfulness, cheer, sunniness, sunshine] [ant: uncheerfulness]

Definition of 'Sunniness'

From: GCIDE
  • Sunniness \Sun"ni*ness\, n. The quality or state of being sunny. [1913 Webster]