Remember Every UTC Offset: A 24-Card Flashcard Guide to World Time Zones

Deck ST2129 "Time Zones" on Flip It is short and unusually practical: 4 concept cards followed by 20 cards that each pair a UTC offset with the countries that use it. You can finish it in two sessions, but two of its conventions need fixing first or you will memorise the wrong thing.

What the 24 cards cover

Definition of a time zone, UTC as the successor to GMT, the full offset range from UTC−12:00 to UTC+14:00, Daylight Saving Time, then the offsets themselves: Baker and Howland Islands, Hawaii and the Cook Islands, the Pitcairn Islands and the US Pacific coast, Colombia, Peru, Panama, Jamaica and Ecuador, Newfoundland, Argentina, Brazil, Uruguay, Suriname and French Guiana, Iceland, Ghana, Senegal, Mali and Burkina Faso, Algeria, Nigeria, Angola, Tunisia and Morocco, South Africa, Botswana, Zimbabwe, Libya and Namibia, Saudi Arabia, Ethiopia, Kenya, Iraq, Turkey and European Russia, Iran, Afghanistan, India and Sri Lanka, Nepal, Myanmar and the Cocos Islands, China, Singapore, Malaysia, the Philippines, Hong Kong, Taiwan and Western Australia, Eucla, the Northern Territory, the Chatham Islands and the Line Islands of Kiribati.

Eight cards from the deck

Fix the DST lines before you start

Seven cards end with a line like "During DST: California, Nevada, Washington, Oregon" under UTC−08:00, or "During DST: UK, Ireland, Portugal" under UTC+00:00. Read literally, that is backwards: California sits at UTC−08:00 during standard time and moves to UTC−07:00 during DST; the UK is UTC+00:00 in winter and UTC+01:00 in summer. The same inversion affects UTC−10:00 (Aleutian Islands), UTC−05:00 (US Eastern), UTC+01:00 (Western Europe), UTC+02:00 (Eastern Europe, Israel, Egypt) and UTC+09:30 (South Australia). Mentally rewrite every "During DST" as "outside DST" and the whole deck becomes consistent.

Second fix: the deck calls both UTC+05:45 (Nepal) and UTC+08:45 (Eucla) "one of only two 45-minute offset zones", then teaches UTC+12:45 for the Chatham Islands a few cards later. There are three, and the Chatham card gets it backwards too: +12:45 is Chatham standard time, +13:45 is its DST value. Fix the count on all three cards.

What the deck leaves out

Sixteen whole-hour offsets are simply absent, including some of the most populated on Earth: UTC+09:00 (Japan, Korea), UTC−06:00 (Chicago, Mexico City, Central America), UTC+10:00 (Sydney, Brisbane), UTC−07:00, UTC−04:00, UTC+07:00 (Thailand, Vietnam, Indonesia) and UTC+04:00 (UAE, Gulf). Writing those eight cards yourself takes ten minutes and doubles the deck's practical value; the exotic fractional zones are the fun part, but the whole hours are what you actually need when scheduling a call.

Drill it by country rather than by offset: shuffle after the first pass and give yourself the country name as the prompt, since in real use you always start from a place, never from a number. For more geography decks, see US National Parks and the UNESCO World Heritage system.

Deck code ST2129 "Time Zones" on Flip It.