阴

阴 (yīn) is the Chinese word for 'overcast / cloudy / shady' — the kind of sky where the sun is fully blocked, not the lighter 多云 (duōyún, 'partly cloudy'). On weather reports, 阴 is the standard label for fully gray days. Beyond weather, 阴 means 'shady / in the shade' (树阴 shùyīn — 'tree shade') and carries the broader cultural concept of yīn from yīn-yáng (阴阳): the cool, dark, feminine, receptive side of dual forces (paired with 阳 yáng — sun, bright, warm, masculine). 阴 also forms compounds with negative connotations like 阴冷 (yīnlěng, 'damp and cold') or 阴险 (yīnxiǎn, 'sinister'), reflecting how 'shadow' and 'cold' link metaphorically. For weather use specifically, just remember: sun out → 晴 (qíng), gray sky → 阴.

Memory hook: The traditional form 陰 has 月 (moon) on the right — 阴 is the moon-side: dark, cool, hidden from the sun.