Vendémiaire was the first month of the autumn quarter (mois d'automne). It started at the autumnal equinox which was between September 22 and September 24. It ended between October 21 and October 23. It follows the Sansculottides of the past year and precedes Brumaire.
Like all FRC months Vendémiaire lasted 30 days and was divided into three 10-day weeks, called décades (decades). Every day had the name of an agricultural plant, except the 5th (Quintidi) and 10th day (Decadi) of every decade, which had the name of a domestic animal (Quintidi) or an agricultural tool (Decadi).
| 1re Décade | 2e Décade | 3e Décade | ||||
| Primidi | 1. | Raisin (Grape) | 11. | Pommes de terre (Potatoes) | 21. | Chanvre (Hemp) |
| Duodi | 2. | Safran (Saffron) | 12. | Immortelle (Strawflower) | 22. | Pêches (Peaches) |
| Tridi | 3. | Châtaignes (Chestnut) | 13. | Potiron (Giant Pumpkin) | 23. | Navets (Turnip) |
| Quartidi | 4. | Colchique (Autumn Crocus) | 14. | Réséda (Mignonette) | 24. | Amarillis (Amaryllis) |
| Quintidi | 5. | Cheval (Horse) | 15. | Âne (Donkey) | 25. | Bœuf (Cattle) |
| Sextidi | 6. | Balsamine (Yellow Balsam) | 16. | Belle de nuit (Marvel of Peru) | 26. | Aubergine (Eggplant) |
| Septidi | 7. | Carottes (Carrots) | 17. | Citrouille (Summer Pumpkin) | 27. | Piment (Chile Pepper) |
| Octidi | 8. | Amaranthe (Amaranth) | 18. | Sarrazin (Buckwheat) | 28. | Tomate (Tomato) |
| Nonidi | 9. | Panais (Parsnip) | 19. | Tournesol (Sunflower) | 29. | Orge (Barley) |
| Decadi | 10. | Cuve (Tub) | 20. | Pressoir (Wine-Press) | 30. | Tonneau (Barrel) |
| Table for conversion between Republican and Gregorian Calendar for the month "Vendémiaire" | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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