From Longman Dictionary of Contemporary Englishthunderythun‧der‧y /ˈθʌndəri/ adjective HEMDNthundery weather is the type of weather that comes before a thunderstorm
Examples from the Corpus
thundery• These showers will gradually spread east and some may become thundery.• The weather looked heavy and thundery, as if the unseasonable warmth would soon break.• So the atmosphere is very thundery at present, and life is anything but gay.• Between searingly bright periods, the sky boils with thundery clouds that drift on by without releasing a drop.• She hadn't had a headache today, in spite of the thundery heat.• There was a rather thundery purple-grey sky and the big trees were swaying about, like restless tied animals. 