The Collaborative International Dictionary of English v.0.48:

Uncommon \Un*com"mon\, a.
   Not common; unusual; infrequent; rare; hence, remarkable;
   strange; as, an uncommon season; an uncommon degree of cold
   or heat; uncommon courage.
   [1913 Webster]

   Syn: Rare; scarce; infrequent; unwonted.
        [1913 Webster] -- Un*com"mon*ly, adv. --
        Un*com"mon*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

uncommonly
    adv 1: exceptionally; "a common remedy is uncommonly difficult
           to find"

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "uncommonly":
   abnormally, abundantly, acutely, amazingly, amply, astonishingly,
   at infrequent intervals, awesomely, conspicuously, copiously,
   eminently, emphatically, exceptionally, exquisitely,
   extraordinarily, extremely, exuberantly, famously, generously,
   glaringly, hardly, hardly ever, impressively, incredibly,
   infrequently, intensely, irregularly, magically, magnanimously,
   magnificently, markedly, marvelously, nobly, not often, notably,
   on occasion, particularly, peculiarly, pointedly, preeminently,
   profusely, prominently, pronouncedly, rarely, remarkably, richly,
   scantily, scarcely, scarcely ever, scrimpily, seldom,
   seldom if ever, signally, singularly, skimpily, sparsely,
   splendidly, sporadically, strikingly, superlatively, surpassingly,
   surprisingly, uncommon, uncustomarily, unexpectedly, unfrequently,
   unnaturally, unoften, unordinarily, unusually, very seldom,
   wonderfully, wondrous, worthily