DateTimeNow

DateTimeNow is a common, language-agnostic label for a call or property that returns the current date and time from the system clock. A DateTimeNow value typically includes year, month, day, hour, minute, second, and sometimes fractions of a second. The timezone semantics vary by environment: some implementations return local time, others return Coordinated Universal Time (UTC), and some provide separate helpers for each.

Examples by language illustrate the variation. In .NET: DateTime.Now yields local time, DateTime.UtcNow yields UTC. In Python: datetime.now() yields local time, datetime.utcnow() yields UTC. In JavaScript: new Date() returns a Date object for the current local time, and Date.now() returns a millisecond timestamp. In SQL: GETDATE() or CURRENT_TIMESTAMP returns the current system date and time.

Common uses include stamping events for logs, records, and audits; generating time-based identifiers; and performing duration or age calculations. Because DateTimeNow reflects the system clock, it is not monotonic and can be influenced by clock adjustments or daylight saving changes.

Practical considerations include choosing an explicit time zone (local vs UTC) when consistency is important; being aware of DST transitions; when serializing across systems, preferring a standardized UTC representation or including time zone information; and considering the required precision for the task at hand, which can vary by language and environment.

See also: Date, Time, Time zone, Timestamp, Clock.