When is it safe to change the date on a watch?
It is safe to change the date on a watch when the hands are well away from midnight: 6:30, morning or evening, is outside every no-go window we have found. Manufacturers give their own windows, from Tissot's 22:00–02:00 to Longines' 20:00–03:00, and some movements give none at all. The table lists each one we have checked, with its source.
Why late evening is the problem
A date doesn't jump at exactly midnight. On most mechanical movements the change starts a couple of hours earlier, as a wheel slowly loads the spring that will flick the date over. While that wheel is engaged, a quick-set from the crown pushes against it. The result can be a date that skips, a date that doesn't change at midnight, or, on some movements, a damaged part. Quartz watches can have the same mechanism, which is why Tissot gives a window for its quartz models too.
No-go hours by brand and calibre
The times are as shown on the dial. A 12-hour dial can't tell you whether "10 o'clock" is morning or evening, so check (see the steps below).
| Watch | Avoid | What the manual says | Source |
|---|---|---|---|
| Tissot quartz (date and moon phase) | 22:00–02:00 | No rapid date or moon phase correction in this window. | TISSOT quartz analogue watches instructions, no. 156 |
| Longines Master Moonphase, calibre L899 | 20:00–03:00 | Avoid any quick date correction in this window. | LONGINES calibre L899 instruction manual |
| Seiko 6R24 and 6R27 | 21:30–02:00 | A "no setting period": the day and date won't move. Seiko says turning the crown then does no harm. | SEIKO cal. 6R20/6R21/6R24/6R27 instructions |
| Citizen Calendrier, calibre 8730 | 21:00–24:00 | If you change the date then, it may not move on at midnight. | CITIZEN cal. 8730 instruction manual |
| Frederique Constant FC-702 to FC-716 (incl. FC-705) | 21:00–03:00 | Move the hands outside 9 pm–3 am first, or the date may not change. | FREDERIQUE CONSTANT FC-701/702/703/705/715/716 manual |
| Frederique Constant FC-330 and FC-335 | Any time except 6–9 | Put the hands between 6 and 9 o'clock (am or pm) before setting the date or moon. Elsewhere, the manual warns of damage that may not be covered by the warranty. | FREDERIQUE CONSTANT FC-330/335 manual |
| Omega Speedmaster Moonphase, calibre 1866 | Hands between 7 and 12 | Don't press the correctors with the hands between 7 and 12 o'clock, am or pm. Don't set the date by moving the hour hand past midnight. | OMEGA operating instructions, 2020 edition: calibre 1866 section |
| Omega date calibres 2500, 8520/8521, 8700/8701, 8800/8801 | 20:00–02:00 | Date setting is "not recommended" in this window. | OMEGA operating instructions — all calibres |
| Other Omega calibres | Varies | Other sections give 8.30 pm–1 am, 10 pm–2 am or 9 pm–12.30 am, depending on the calibre. Check your calibre in the manual. | OMEGA operating instructions — all calibres |
| Omega Speedmaster Moonphase, calibres 9904 and 9914 | None stated | Omega's instructions give no window. Avoiding about 9 pm to 3 am is our own precaution. | OMEGA operating instructions — all calibres |
| Jaeger-LeCoultre Master Ultra Thin Moon, calibre 925 | None stated | The manual we read gives no window for the correctors. | JAEGER-LECOULTRE Master Ultra Thin Moon, calibre 925 manual |
The Frederique Constant manuals are in Japanese; the wording above is our translation.
How to change the date safely on any watch
- Park the hands at 6:30
Pull the crown fully out and turn the hands to about 6:30. That is outside every window in the table.
- Set yesterday's date
Push the crown in to the first click (or use the date corrector) and set the date to yesterday's.
- Turn the time forwards through midnight
Pull the crown fully out and turn the hands forwards. When the date flips, that was midnight. Carry on to the right time and push the crown in.
Going through midnight on the last step also settles morning versus evening: the date can only flip at midnight, so after it flips you know where you are.
Related guides
Sources
- TISSOT quartz analogue watches instructions, no. 156 (manufacturer PDF)
- LONGINES calibre L899 instruction manual (manufacturer PDF)
- SEIKO cal. 6R20/6R21/6R24/6R27 instructions (manufacturer)
- CITIZEN cal. 8730 instruction manual (manufacturer PDF)
- FREDERIQUE CONSTANT FC-701/702/703/705/715/716 manual (manufacturer PDF, Japanese)
- FREDERIQUE CONSTANT FC-330/335 manual (manufacturer PDF, Japanese)
- OMEGA operating instructions, 2020 edition: calibre 1866 section (manufacturer PDF, archived copy)
- OMEGA operating instructions — all calibres (manufacturer PDF)
- JAEGER-LECOULTRE Master Ultra Thin Moon, calibre 925 manual (manufacturer PDF)