Wrong time on your device: clock error or time-zone error?
Separate an inaccurate clock from the wrong regional setting before changing your device's time manually.
Compare the same place first
If your phone and a website disagree, first check that both are displaying the same city. The clock for New York is not a test of your own local time unless that is the zone you intend to use. A difference of exactly one hour often suggests a seasonal rule or zone setting, but the size alone cannot prove the cause. Record the date, selected city and displayed time so you can compare like with like instead of repeatedly adjusting the hands.
Check the regional rule and the clock separately
A device can know the correct global instant and still show the wrong local hour because its time-zone database is old. IANA maintains these regional rules, while manufacturers distribute updates on their own schedules. Check automatic date-and-time and automatic time-zone settings separately, then install relevant system updates. A manually selected UTC offset may look correct today and fail after a seasonal change. Use a named regional zone when the device supports it; see how time-zone updates work.
Confirm appointments after fixing the setting
Do not compensate for a zone error by moving every appointment or manually shifting the system clock. Compare an upcoming entry with the organizer's stated city and date using the time converter. Check another entry after the next seasonal transition if it repeats. If a website alone is wrong, note the selected location and whether the page is showing an offline estimate. The guide to UTC and local time helps explain why one instant can legitimately have different local labels.
Sources
Related reading
Why time-zone data updates matter even when your clock looks right
A policy change has to reach your software before future local times can be calculated correctly.
UTC and local time: a practical explanation
Learn what an offset tells you, what it leaves out and how to write an unambiguous time.