Glossary · Complication
Annual calendar
A calendar mechanism that correctly tracks 30- and 31-day months without adjustment, requiring a single correction at the end of February.
Explanation
An annual calendar distinguishes 30- and 31-day months automatically and needs manual correction only once a year, at the end of February. Patek Philippe patented the modern wristwatch version in 1996, though the idea is older in clocks. It sits between the simple calendar (corrected five times a year) and the perpetual calendar (corrected only in 2100).
In the object catalogue
Catalogued objects whose own source record mentions “Annual calendar”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.
Wristwatch
Christiaan van der Klaauw CVDK Planetarium ref. CKPT33B4
“This Christiaan van der Klaauw CVDK Planetarium wristwatch, reference CKPT33B4, features a round 40 mm stainless steel case housing a dark aventurine dial with Roman numeral hou…”
Wristwatch
Patek Philippe 'Gondolo' Annual Calendar Ref. 5135R-001
“Patek Philippe 'Gondolo' Annual Calendar Ref. 5135R-001”
Wristwatch
Patek Philippe Annual Calendar Ref. 5036/1G-013
“Patek Philippe Annual Calendar Ref. 5036/1G-013”
Wristwatch
Patek Philippe Ref. 5235G-001 Annual Calendar Regulator
“Patek Philippe Ref. 5235G-001 Annual Calendar Regulator”
Wristwatch
Patek Philippe Ref. 5235G-001 Regulator Wristwatch
“This Patek Philippe reference 5235G-001 is an 18K white gold annual calendar regulator wristwatch measuring 40.5 mm in diameter, dated circa 2015. The source reports that it is …”
Wristwatch
Patek Philippe Nautilus Annual Calendar Ref. 5726/1A-001
“Patek Philippe Nautilus Annual Calendar Ref. 5726/1A-001”