Definitions

Unpleasant \Un*pleas"ant\, a.
     Not pleasant; not amiable or agreeable; displeasing;
     offensive. -- {Un*pleas"ant*ly}, adv. -- {Un*pleas"ant*ness},
     n.
 
     abhorrent, bad, bitter, disagreeable, dislikable, displeasing,
     distasteful, foul-tasting, ill-flavored, intolerable, mislikable,
     odious, rotten, sour, thankless, ugly, unalluring, unappealing,
     unappetizing, unattractive, uncongenial, undelectable, undelicious,
     undesirable, unengaging, unenjoyable, unhappy, uninviting,
     unlikable, unlovable, unpalatable, unpleasing, unsavory,
     untasteful, untasty, unwelcome

The weather in Melbourne is extremely unpleasant.

Extremely.