monthnum is a WordPress query string variable that stores the two digit month number. It can be used to retrieve archive of posts posted in a certain month, even across years. When a particular post is being displayed, it contains the month when the post was published.
WordPress uses this global variable internally when the archives are requested. Plugin and theme developers can use
monthnum to access the month requested or for the month of the current post. Day f the current post can be accessed using day.
Back to full list of global variables.
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