"a new code or something, like the colors of the day"

Although Thai astrology assigns a color to each day of the week, in the military the phrase “colors of the day” refers to color coding to communicate the level of danger anticipated on a particular day, starting with code white (fairly secure) and ascending through code yellow and orange to code red (in conflict and under immediate threat).

Similarly, in law enforcement, the phrase refers to a color code used to identify comrades in order to minimize fatal accidents by “friendly fire.” In the New York City Police Department, for example, a color of the day, assigned each morning, enables uniformed officers to recognize plainclothes and undercover cops. The latter wear a headband, wristband, or other article of clothing in that color for that day.