Programmer's Day, also called "Overflow Day". On July 24, 2009, the Ministry of Communications and Mass Media of the Russian Federation proposed the Programmer's Day plan; on September 11, Russian President Medvedev signed the bill, agreeing to establish Programmer's Day. The date is the 256th day of each year, which means the overflow of one byte (8 bits) (starting from 0, the maximum is 255), that is, September 13 in common years and September 12 in leap years.

The reason for choosing 256 (2^8) is that it is a basic 8-bit number well known to programmers. One byte (equal to 8 bits) can represent up to 256 values, and in a common year, 256 is the largest power of 2 that is less than 365.

The establishment of this holiday is credited to Valentin Balt, an employee of Parallel Technologies web design company. In 2002, he collected signatures and petitioned the Russian Federation government to designate this day as Programmer's Day. On July 24, 2009, the Ministry of Communications and Mass Media of the Russian Federation proposed a new holiday arrangement plan to establish Programmer's Day. On September 11, Russian President Medvedev signed the bill.

White has been chosen as the theme color for Programmer's Day.

In the red-green-blue 24-bit (RGB) color space, each primary color can have 256 levels of intensity (256 values from 0 to 255). When all three primary colors reach their maximum intensity values, which is hexadecimal 0xFFFFFF, it represents white. Therefore, programmers all over the world wear white to celebrate this day.