Concept
Haab’
The 365-day Maya year: 18 periods of 20 days, plus the five-day Wayeb’. It approximates the tropical year and has no leap-day correction in its ordinary structure.
Unknown Maya scribe; photograph of a public-domain manuscript, “Dresden Codex, page 49”, Public domain, via Wikimedia Commons
A fixed Haab’ date therefore drifts against the seasons. Astronomical observation, not the calendar arithmetic itself, kept ceremony and agriculture aligned. Wayeb’ was treated in many traditions as a sensitive, transitional span.