dry season has no recorded synonym. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is rainy season.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
one of the two seasons in tropical climates
Synonyms, antonyms and the broader and narrower relations for dry season come from Princeton University’s WordNet. Full sources and licences.