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Calendar.IsLeapMonth Method (Int32, Int32, Int32)

When overridden in a derived class, determines whether the specified month in the specified year in the specified era is a leap month.

Namespace:  System.Globalization
Assembly:  mscorlib (in mscorlib.dll)

public abstract bool IsLeapMonth(
	int year,
	int month,
	int era


Type: System.Int32
An integer that represents the year.
Type: System.Int32
A positive integer that represents the month.
Type: System.Int32
An integer that represents the era.

Return Value

Type: System.Boolean
true if the specified month is a leap month; otherwise, false.


year is outside the range supported by the calendar.


month is outside the range supported by the calendar.


era is outside the range supported by the calendar.

To make up for the difference between the calendar year and the actual time that the earth rotates around the sun or the actual time that the moon rotates around the earth, a leap year has a different number of days from a standard calendar year. Each Calendar implementation defines leap years differently.

A leap month is an entire month that occurs only in a leap year. For example, in the Hebrew calendar, Adar Beit is the only leap month.

Notes to Inheritors

The derived class must support CurrentEra when it is passed as the era parameter. One way to support CurrentEra is by replacing it with the value stored in Eras[0], which is the value for the current era of the calendar.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.