Seiko C-21 - Time Zone Display and Time Difference Table; What Is a Time Zone

The radio signal transmitting station can be changed by selecting the time zone.
When selecting a time zone for regions other than the radio signal reception ranges,
the radio signal reception function will not work.
* When setting the daylight saving time (DST), add one hour to the time zone of the target area.
In Japan In China In the other countries
Set the seconds hand to
the 23-second position.
Set the seconds hand to
the 21-second position.
“Time zone display
and time difference
table” → P.33
3
Wait for ten seconds after the movement of the hour and minute hands stop. (The
time zone adjustment mode is finished.)
The seconds hand starts to move.
The watch automatically adjust the date and day of the week as necessary.
* While the date and day of the week are moving, neither the buttons nor the crown can be operated.
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WORLD TIME FUNCTION
Time zone display and time difference table
In time zone selection mode, move the seconds hand to the time zone display of the target area as shown below.
When setting daylight saving time (DST), add a time difference of +1 hour to the time zone of the target area.
Time zone
display
Time
difference
display
Seconds hand positions
Names of
representative
cities (Time zone)
Time
difference
from UTC
Receivable radio
signals
LON UTC 0-second position London ±0 hours MSF/DCF77
PAR/BER 1 3-second position Paris/Berlin +1 hours MSF/DCF77
CAI 2 6-second position Cairo +2 hours MSF/DCF77
JED 3 8-second position Jeddah +3 hours DCF77
DXB 4 11-second position Dubai +4 hours DCF77 △
KHI 5 13-second position Karachi +5 hours -
DAC 6 15-second position Dhaka +6 hours -
BKK 7 18-second position Bangkok +7 hours -
BJS/HKG 8 21-second position Beijing/Hongkong +8 hours BPC
TYO 9 23-second position Tokyo +9 hours JJY
SYD 10 25-second position Sydney +10 hours JJY △
NOU 11 28-second position Nouméa +11 hours -
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WORLD TIME FUNCTION
* Time zones marked with a △ in “Receivable radio signals” are selected when the time zone one hour earlier is set to daylight
saving time (DST).
* Each indication may differ depending on the model (design) of the watch.
(As of August 2020)
Time zone
display
Time
difference
display
Seconds hand positions
Names of
representative
cities (Time zone)
Time
difference
from UTC
Receivable radio
signals
WLG 12 30-second position Wellington +12 hours -
TBU 13 32-second position Nuku’alofa +13 hours -
MDY -11 34-second position Midway Islands -11 hours -
HNL -10 36-second position Honolulu -10 hours -
ANC -9 38-second position Anchorage -9 hours -
LAX -8 41-second position Los Angels -8 hours WWVB
DEN -7 43-second position Denver -7 hours WWVB
CHI -6 45-second position Chicago -6 hours WWVB
NYC -5 48-second position New York -5 hours WWVB
SDQ -4 50-second position Santo Domingo -4 hours WWVB △
RIO -3 53-second position Rio de Janeiro -3 hours -
FEN -2 55-second position
Fernando de
Noronha
-2 hours -
PDL -1 57-second position Azores -1 hour -
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WORLD TIME FUNCTION
■ What is a time zone?
Based on Coordinated Universal Time (UTC), the standard time commonly used is adopted by
countries and regions around the world.
The standard time is determined by each country or region, and the region where the same
standard time is adopted is referred to as the time zone.
Further, Daylight Saving Time (DST) is individually adopted in countries and regions.
[What is UTC (Coordinated Universal Time)?]
UTC is the universal standard time coordinated through international agreement. It is used as the official
time around the world. UTC is a time coordinated by adding leap seconds to the “International Atomic
Time (TAI)” determined from atomic clocks in the world, in order to correct the deviation from the
astronomically defined universal time (UT).
[What is summer time (DST)?]
Summer time is Daylight Saving Time (DST).
Advance the watch one hour to prolong daytime during longer daylight hours in summer.
The adoption and duration of Daylight Saving Time (DST) vary depending on the country.
* Time differences between regions and daylight saving time may change due to circumstances of a country or
region.
* In some regions, time zones that differ from UTC by half- or quarter-hour time differences are established. (For
example, some parts of India)
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WORLD TIME FUNCTION