当天的颜色（）是一个美国警察术语，表示一些警察局识别便衣警察的颜色信号。 当天颜色的主要用途，是用于帮助穿着制服的持枪警察，能够识别穿着便装执勤的便衣警察，避免执法时误伤同僚，纽约市警察局和其他执法机构都有使用这个方法。 目的是为了能更有效地保护执勤的便衣警察，比如纽约市有数量庞大的持枪警察，彼此之间互不相识，所以便衣警察需要一套易于使用的系统，以便制服警察能够谨慎且迅速地识别便衣警察，避免将持枪的便衣误认为坏人而被射击。

便衣警察会佩戴当天指定颜色的制式、腕带或其他服饰配件 这个系统最早于1970—80年代，在纽约市频频发生的暴力事件开始实行。 便衣警察被要求穿着便衣，进入纽约地铁和其他高危地区，或装扮成露宿者作为诱饵，诱骗那些以高危群体为目标的歹徒。许多便衣警察因此担心，在使用武力的情况下，穿制服的警察会将他们误认为罪犯； 因此，执法当局发明佩戴当天颜色相同的头带或腕带，以防止可能出现的误伤事件。

• In Law & Order Season 5, Episode 20, "," Detective identifies the color of the day as aquamarine when making an inquiry to the DMV.

Color of the day is mentioned in Special Victims Unit* episodes "", "", "Gambler's Fallacy", and "".
*Color of the day is also mentioned in Blue Bloods, , Episode 19, "Loss of Faith", when says that every plainclothes officer will have the color of the day in full display, , Episode 9, "Pain Killers", when Frank Reagan asks if an NYPD plain clothes officer who was shot at by a officer was wearing the color of the day, and in , Episode 19, "Family Affairs", when the same Reagan identifies the color of the day as green after noticing a green wristband worn by NYPD plainclothes officer Joe Hill.
*In season 6 episode 8 "Raging Bulls" an undercover officer is shot by another police officer while not wearing the color of the day (red).
*In Shooter (TV series) Season 1, Episode 1, "Point of Impact", Bob Lee Swagger (played by Ryan Phillippe) recognizes a United States Secret Service agent (Isaac Johnson, played by Omar Epps) by their lapel pin which was the color of the day.
*In White Collar (TV series) Season 2, Episode 4, "By the Book", the color of the day is set to orange by FBI Agent Peter Burke in a preparation meeting to arrest a Colombian crime boss.

另见

• 纽约市执法部门

注解

便衣警察不等于卧底警察，便衣警察并不掩饰自己带着警枪和手铐，以及警察随身摄像机等其他明显的执法标志；换而言之，便衣警察与制服警察有相同的基本装备，但不会通过穿着制服来显示他们的警察身份。相反，卧底警察会采取积极措施，隐瞒他们与执法部门的关系。

参考资料