«زَيِّ نَهَارِ الشِّتَا مَالُوشْ أَمَانْ»

A clear winter day can turn cold, windy or wet within hours, so its brightness is no promise of what comes next. The saying uses that unsettled sky as its picture: a pleasant spell in winter gives no assurance that it will last.

Applied to people, it describes someone quick to anger whose calm or friendly moments cannot be counted on. The point is not coldness but untrustworthy calm: however agreeable such a person seems, they may suddenly turn and do or say something unwelcome.

Said casually about a person whose good humor can flip without warning into irritation or anger. It works as an everyday caution to others not to grow too comfortable during that person's pleasant moods, since something unpleasant may follow.