When the watch is unable to adjust its time in accordance with a calibration signal for some reason, average timekeeping accuracy is within ±15 seconds per month.
Note that an internal decoding process the watch performs after it receives a signal may cause the time setting to be slightly off (by less than one second).
Time calibration signal reception is not possible under the conditions described below.
While battery power is low
In any mode besides the Calendar Mode
While the watch is at Level 3 power saving
While the crown is pulled out
While a timer countdown operation is in progress
While the Home City setting is a time zone where time signal reception is not possible
While the watch is outside the time signal reception range
While the Airplane Mode is enabled
When the receive operation is successful, the time and/or day settings will be adjusted automatically. Summer time will not be applied correctly in the case described below.
When the summer time start date and time, end date and time, or other rules are changed by authorities
If your watch is connected with a phone, settings must be configured so CASIO WATCHES can acquire location information. Even if you are in an area that is within the reception range of a time signal, reception will not be performed if settings are configured in a way that makes signal reception impossible.
As of January 2020, China does not observe summer time. If China starts to observe summer time in the future, the time displayed by the watch for China may not be correct.