Catalyzes the formation of flavonols from dihydroflavonols. Acts on (2S)-naringenin and (+)-trans-dihydrokaempferol to produce kaempferol and on (2R)-naringenin to produce (-)-trans-dihydrokaempferol. 2-oxoglutarate + a (2R,3R)-dihydroflavonol + O2 = a flavonol + CO2 + H2O + succinate 2-oxoglutarate + a (2S)-flavan-4-one + O2 = a (2R,3R)-dihydroflavonol + CO2 + succinate Binds 1 ascorbate molecule per subunit. Binds 1 Fe cation per subunit. Secondary metabolite biosynthesis; flavonoid biosynthesis. Belongs to the iron/ascorbate-dependent oxidoreductase family.