Duōyún zhuǎn yīn de tiānqì zuì róngyì ràng rén fànkùn.
Cloudy-turning-overcast weather makes people sleepiest.
Tips
usage
阴 in weather terms = 'overcast' (full cloud cover, but not raining); 多云 = 'partly cloudy'. The 转 pattern gives the order: what the day starts as, then turns into.
