Unflecked

The ceaseless motion of the vessel rocking at the centre of a circular space of blue, with a perfectly symmetrical dome of azure enclosing her above, unflecked by a single cloud, becomes at last almost unbearable from its changeless sameness of environment.

Source: wiktionary

Shores that Stella had last seen dismal and forlorn in the frost-fog, sheathed in ice, banked with deep snow, lay sparkling now in warm sunshine, under an unflecked arch of blue.

Source: wiktionary