Which way should I display time zone names to make them easily pickable?

1. How are time zones chosen?
2. How do you list time zones in an email?
3. How are time zones numbered?

How are time zones chosen?

The Earth is loosely divided into 24 regions (time zones) separated by longitude. Not counting local variations, each line of longitude is divided by fifteen degrees; as a general rule and depending upon which way one travels, time moves forward or backward one hour for every fifteen degrees of longitude.

How do you list time zones in an email?

Reference to a specific time and zone would follow standard guidelines with the zone in parentheses: 4:42 p.m. (PST), 11:03 a.m. (MDT), 2:30 p.m. (CST), 10:00 P.M. (EST). AP on the other hand advises to capitalize the full name of each time zone: Pacific/Mountain/Central/Eastern Standard Time.

How are time zones numbered?

Each time zone spans 15 degrees of longitude. The "zero" zone is centered on the Prime Meridian which passes through Greenwich, England; it extends east to 7.5°E and west to 7.5°W. The zones are numbered negatively to the west and positively to the east of Greenwich.