WordNet sense 1 (humble in spirit or manner; suggesting retiring mildness or even cowed submissiveness):

meek, modest

WordNet sense 2 (marked by meekness or modesty; not arrogant or prideful):

humble

WordNet sense 3 (not extreme):

moderate, temperate, moderate

WordNet sense 4 (soft and mild; not harsh or stern or severe):

gentle, soft

WordNet sense 5 (mild and pleasant):

balmy

WordNet sense 6 ((of weather or climate) physically mild):

clement