Here Colorado native “mapguy” states,
 Quote:
Colorado: we natives pronounce it call-uh-RAD-o (the accented syllable rhymes with "bad"). We figure anyone who says call-uh-ROD-o or call-uh-ROD-der must be either a tourist or a short-time resident (when they pronounce the accented syllable as if it rhymes with "pod"). Despite what you may hear on local newscasts, we're call-uh-RAD-o-uns (five syllables), not call-uh-ROD-uns (four syllables).