How many months did the Maya Haab' calendar contain?

How many months did the Maya Haab' calendar contain? The Haab' calendar contained 18 months. Each month had 20 days, giving 360 named days, followed by a separate five-day period called Wayeb' to complete the 365-day year.

The Haab' was the Maya solar calendar, though it did not include a leap-day correction like the modern Gregorian calendar. Its 18 regular months had distinct names, including Pop, Sip, Yax, and Kumk'u. The final five days, Wayeb', were considered an unusual or potentially unlucky transition period rather than a normal month.

The number 20 is a common trap because each Haab' month contained 20 days. Thirteen is associated with the numbers of the sacred Tzolk'in calendar, which interlocked with the Haab' in Maya calendrical cycles. The two calendars formed a 52-year Calendar Round before a particular combination of dates repeated. Thus, the Haab' had 18 months, plus Wayeb' outside those regular months.