Timezones

The basic information for this table is found in Randy Jacobson's work, "Time Zones for Earhart Radio Message Database."

From local to GMT

To determine how to get back to GMT time from a local time, always add the offsets given below to get GMT time.

From GMT to local

Subtract the value of the offset from GMT to get the local time.

Math reminders

• When we add negative numbers, the result is the same as subtracting the absolute value of the number from the base.

0000 GMT + (-1) = 0000 - 0100 = 2300

• When we subtract negative numbers, the result is the same as adding the absolute value of the number to the base.

0000 GMT - (-1) = 0000 + 0100 = 0100

1937 timezones.

Ship/Place	Time of TZ Change	Offset from GMT
Howland		10.5
Jarvis		10.5
Baker		11
Honolulu		10.5
San Francisco		8
Washington, DC		5
London		-1
American Samoa		11
CINCUS		8
COMINBATFOR		10.5
COMDESCOFOR		8
COMAIRBASEFOR		8
COMBATSHIPS		8
COMAIRBATFOR		8
Duane	13 Jan 1937	10.5
	15 Jan 0530	11
	24 Jan 1300	10.5
Shoshone	March 10, 0700	10.5 (stays 10.5 for duration of first attempt)
Itasca	19 June 0000	10.5
	20 June 1400	11
	22 June 1400	11.5
	12 July 1400	12
	14 July 0000	11.5
	20 July 1400	11
	23 July 0800	10.5
Ontario	17 June 1937	0700 11
	18 June 0000	12
	20 June 1100	-12
	22 June 1800	-11
	5 July 0800	-12
	7 July 1500	12
	9 July 1500	11
Swan	1 July 0000	11
	6 July 1300	11.5
	10 July 0300	11
	10 July 1700	11.5
	12 July 1900	12
	15 July 0000	-12
Colorado	3 July 1400	10.5
	4 July 4 1300	11
	7 July 1300	11.5
	14 July 1300	10.5
Lexington Drayton Cushing Lamson	1 July 1937	8
	5 July 1600	9
	7 July 1600	10
	8 July 1030:	10.5
	12 July	11.5
	21 July	10.5

Links

• Transmission timeline