resetWhen you cross a time zone, local clock subtraction can give the wrong duration. Record the dates and zones as well as the clock times. Travel does not make a timer a medical recommendation to continue fasting during a journey.
Compare elapsed time with local time
Suppose an interval starts at 8 pm in a zone at UTC+10. That instant is 10 am UTC. It ends at 8 am the following local day in a zone at UTC+8, which is midnight UTC.
The actual interval is 14 hours. Simply subtracting 8 pm from 8 am would suggest 12 hours and miss the two-hour zone difference.
Use the offsets that apply on the travel date. Some places change offsets seasonally.
Keep a small travel note
Before travelling, note the actual start and its local time zone. At the end, note the actual end and its zone. A phone normally updates its local zone automatically, but a handwritten local time without its zone becomes ambiguous later.
Reset stores session times as timestamps and displays them using the device’s local time context. Existing displayed hours and end-date groupings may therefore look different after a zone change.
Be careful with manual corrections
When entering an old session after arrival, do not blindly type the departure city’s clock time into an editor using the destination’s zone. Convert both endpoints to the same zone first and verify the resulting duration.
If you cannot establish the times accurately, avoid making a precise-looking entry from a guess. You can keep the original note separately.
Do not use the website calculator for flights
The schedule calculator assumes a regular 24-hour cycle and does not model travel or changing time-zone offsets.
See the daylight-saving guide for a similar issue without a flight. During travel, meals, hydration needs and medical instructions take precedence over preserving a timer target. Reset records your timing; it does not generate a travel nutrition plan.