yearmonth

YearMonth is a representation of a specific year and month, without any day, hour, or time zone. It captures the calendar month in a given year and is often used for monthly reporting, billing cycles, and scheduling where day granularity is unnecessary.

In ISO-8601, a year-month value is written as YYYY-MM, such as 2024-07. Many programming languages provide a dedicated YearMonth type or a similar concept. For example, in Java 8 and later, java.time.YearMonth stores a year and a month and offers methods to add or subtract months, compare values, or convert to other date types. Its string representation is YYYY-MM, and it can be parsed via standard formatters.

Usage and storage: YearMonth is convenient for monthly aggregation, financial periods, or subscription terms. When persisting, you can store as a text in the format YYYY-MM or encode as an integer YYYYMM; some databases use a date with the first day of the month to leverage date arithmetic while keeping day neutral.

Considerations: Because it omits days, the concept does not express daily accuracy and can interact with end-of-month logic; operations crossing month boundaries should handle varying month lengths. Time zones are also irrelevant at this granularity. In data processing, ensuring consistent interpretation of leading zeros (e.g., months 01–12) is important.