clement
Word family
Synonym discussion
Sense: adjective/1
All four words can describe pleasant weather, but they are not used in the same way. 'Clement' is the most formal and often appears in writing about weather that is unexpectedly gentle for a season or place. 'Mild' is the everyday choice and can describe anything from a soft winter to a warm evening. 'Temperate' usually talks about a region or climate pattern, not one afternoon, and suggests moderation across the year. 'Balmy' points to warm, soft air and often gives a more relaxed, holiday-like feeling. So you might call April unusually clement, say today's weather is mild, describe coastal Portugal as temperate, and call an evening by the sea balmy.
Etymology
From Latin 'clemens', meaning 'mild', 'gentle', or 'merciful'. English took the word through Old French and Middle English. The Latin meaning already covered both gentle conditions and forgiving behaviour, which is why modern English still uses 'clement' both for mild weather and for merciful treatment.
First known use
15th century
15th century, in the meaning defined at sense 1