Guru asta is a specific period in Hindu calendars. During this period no auspicious ceremonies are held in North India. Guru Astha 2018 time and date is given below:
Guru Ast is from November 12, 2018 to December 10, 2018. Marriages are not performed during the period. Thus you will not find Marriage dates and other auspicious function dates in November 2018
The total number of days in a Guru Asta are 28 days. Roughly a month.