1. sunniness(n = noun.attribute) - lightness created by sunlight;
is a kind of light, lightness
has particulars: cloudlessness
2. sunniness(n = noun.attribute) cheer, cheerfulness, sunshine - the quality of being cheerful and dispelling gloom; "flowers added a note of cheerfulness to the drab room"
is a kind of attribute
is a part of disposition, temperament
has particulars: good-humoredness, good-humouredness, good-naturedness, good-temperedness
Derived form adjective sunny1
The quality or state of being sunny. [1913 Webster]