One second.
A different century.
On 19 January 2038, seconds since the Unix epoch stop fitting in a signed 32-bit integer. The calendar keeps moving. The representation runs out.
Signed 32-bit time
Within signed 32-bit rangeBoth representations preserve these seconds. The leading bit determines the sign of the 32-bit value.
2,147,483,647It's a limit, not a date bug.
Unix time counts seconds from 1 January 1970. In a signed 32-bit representation, one bit contributes the sign and the remaining 31 bits constrain the positive range.
That final positive second is 2038-01-19 03:14:07 UTC. One more second is outside the range.
What could be affected?
Software, stored data, protocols, and embedded devices that still rely on signed 32-bit timestamps. A modern computer can still run old code with a narrow time representation.
Failures vary: rejected dates, incorrect comparisons, bad scheduling, or other undefined behavior. This lab shows one familiar wrapping model, not a universal crash.
Until the boundary
19 January 2038 · 03:14:08 UTC