RRULEFREQMINUTELYBYSECOND030

RRULEFREQMINUTE refers to using a recurrence rule with a frequency set to minutes (FREQ=MINUTE) in the iCalendar RRULE specification. RRULE is the standardized way to describe repeating events in calendar data, and FREQ indicates the time unit of repetition. When FREQ is set to MINUTE, the rule defines recurrences that occur at regular minute intervals.

In practice, a rule with FREQ=MINUTE is typically refined with an INTERVAL value to specify the step size between occurrences. For example, INTERVAL=5 creates an event that repeats every five minutes. The first occurrence is anchored to the event’s DTSTART value, and subsequent occurrences follow the specified interval. COUNT and UNTIL can be used to limit the total number of occurrences or to stop the recurrence at a particular date/time.

BYSECOND and related refinements can be used to specify more precise timing within each minute, though most minute-based recurrences align to whole-minute boundaries. When combining with BYSECOND, CARE must be taken to ensure consistent interpretation across calendar clients.

Practical use cases include high-frequency reminders, monitoring checks, or time-based triggers that must occur at regular minute intervals within a single day or across multiple days. However, minute-level recurrences can produce a large number of instances, which may affect performance or readability in calendars that support long-running schedules.

Example:

DTSTART:20240501T100000

RRULE:FREQ=MINUTE;INTERVAL=15;COUNT=10

This defines ten occurrences starting at 10:00, then at 10:15, 10:30, and so on, each five minutes apart.

Notes: RRULE syntax also supports UNTIL to set a calendar-wide end date. Always consider client compatibility, as some systems handle minute-based recurrences differently or with limited precision.