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50 free Time Zones trivia questions with answers — geography quiz, new questions added Aug 2026.
Every place on Earth once kept its own solar time, and it took railways, telegraphs and a great deal of argument to sort the planet into zones. The result is gloriously untidy: China runs on a single clock across five geographic zones, India and Nepal sit on half- and quarter-hour offsets, France keeps German wartime time, and Kiribati moved the International Date Line a thousand kilometres east so it could greet the year 2000 first. This quiz tours that history and its oddities: the Day of Two Noons in 1883, Sandford Fleming's 24 zones, why UTC is abbreviated the way it is, where leap seconds come from, what "Zulu time" means, who really proposed daylight saving, the Friday Samoa deleted in 2011, and the 3.5-hour jump at the Afghanistan–China border. Fifty questions from easy to hard, every answer sourced, each explanation adding one more detail for the next trip across the date line.
30 of 50 questions with answers and explanations. Play the quiz
Q 01What is the full range of standard UTC offsets in use around the world?
UTC−12:00 to UTC+14:00
Most offsets are whole hours, but a few zones add 30 or 45 minutes, as in India and Nepal.
Q 02Solar time shifts by how much for every degree of longitude?
Four minutes
That is why solar noon in Bristol comes about ten minutes after London's; Bristol lies 2.5 degrees west.
Q 03Which British rail company began using Greenwich Mean Time in November 1840?
Great Western Railway
Portable chronometers carried the time; other companies followed and it became known as "railway time".
Q 04When did GMT become the legal time for Great Britain?
1880
By 1855 some 98 per cent of public clocks already showed it; some clocks had two minute hands, one local and one GMT.
Q 05Which colony adopted a nationwide standard time in 1868, 11½ hours ahead of GMT?
New Zealand
It was based on longitude 172°30′ east and called New Zealand Mean Time.
Q 06Which US meteorologist divided the country into four zones for his weather stations?
Cleveland Abbe
His 1879 Report on Standard Time helped persuade the railroads in 1883 and, eventually, the US government.
Q 07November 18, 1883, when US railroads reset their clocks, is remembered as what?
The Day of Two Noons
Station clocks were reset as standard-time noon arrived in each zone; the zones were drawn through stations in major cities.
Q 08Which US city kept local time until 1900 and only settled on Eastern Time in 1915?
Detroit
It lies about halfway between the Eastern and Central meridians and tried Central, local mean and Eastern time in turn.
Q 09In which year did the US Congress formally adopt standard time zones?
1918
The Standard Time Act of March 19, 1918, also introduced daylight saving as a wartime measure.
Q 10Who proposed a worldwide system of 24 time zones in 1876?
Sandford Fleming
The Scottish-born Canadian labelled his zones A to Y, skipping J; each covered 15 degrees of longitude.
Q 11Which Italian mathematician first floated worldwide time zones in an 1858 book?
Quirico Filopanti
His book Miranda! proposed 24 "longitudinal days" centred on Rome, but attracted no attention until long after his death.
Q 12Which country was the last to adopt a standard offset, moving to UTC+05:45 in 1986?
Nepal
It had used Indian Standard Time since 1920, then advanced its clocks by 15 minutes.
Q 13How many time zones does Russia have?
11
Two were removed in 2010 and restored in 2014; about 63 per cent of Russians live on Moscow time.
Q 21Leap seconds were first added to UTC in which year?
1972
They keep UTC within 0.9 seconds of Earth's rotation; a 2022 resolution aims to abolish them by 2035.
Q 22UTC is derived from which reference scale, a weighted average of hundreds of clocks?
International Atomic Time (TAI)
TAI is a weighted average of hundreds of atomic clocks; GPS time runs exactly 19 seconds behind it.
Q 23Which time standard does the International Space Station normally keep?
UTC
Orbiting crews see many sunrises a day, so missions usually run on the launch site's or mission control's time.
Q 14China spans five geographic time zones but officially observes how many?
One
It is the largest country to do so; in far-western Xinjiang solar noon can fall as late as 15:00 Beijing time.
Q 15Xinjiang's unofficial local clock, two hours behind Beijing, is named for which city?
Ürümqi
Offices there commonly open at 10:00 Beijing time, which is 08:00 locally; TV channels are scheduled by ethnicity.
Q 16Which land border has the greatest time-zone jump on Earth, 3.5 hours?
Afghanistan–China
You step from UTC+04:30 to UTC+08:00 at the Wakhjir Pass.
Q 17What is the UTC offset of Indian Standard Time?
UTC+05:30
It was adopted in 1906; Kolkata and Mumbai kept their own local times until 1948 and 1955.
Q 18Tea gardens in which Indian state run an hour ahead of IST on "Bagan time"?
Assam
The sun rises almost two hours earlier on India's eastern border than in the far west, yet the country keeps one zone.
Q 19What is the letter designation for the zero-UTC-offset zone, giving it its nickname?
Z, hence "Zulu time"
Greenwich was the point of origin of the lettered zones; pilots everywhere file flight plans in Zulu.
Q 20Why is Coordinated Universal Time abbreviated UTC rather than CUT?
A compromise to match all languages
The ITU and IAU wanted one abbreviation everywhere; UTC also fits the pattern of UT0, UT1 and UT2.
Q 24A Martian solar day, used by some rover teams, is called what and how long is it?
A sol, about 24 h 40 min
Earth controllers for solar-powered rovers have synchronised their sleep cycles to the Martian day.
Q 25Which year did France officially adopt GMT+0 as its time, after decades on Paris time?
1911
Paris mean time ran 9 minutes 21 seconds ahead of Greenwich; the railways had lagged it by a further five minutes for latecomers.
Q 26France still keeps UTC+01:00 because of what historical event?
German occupation in World War II
The Netherlands had run on "Amsterdam Time", 20 minutes ahead of GMT, before being forced onto German time as well.
Q 27With its overseas territories, France spans how many time zones, the most of any country?
12
Thirteen if you count its claim in Antarctica; every overseas territory runs on a different zone from Paris.
Q 28The International Date Line roughly follows which meridian?
180°
It is a cartographic convention, not international law, so countries have moved it for convenience.
Q 29Crossing the date line eastbound does what to the calendar?
Moves it back one day
Westbound travellers skip forward a day; Magellan's crew discovered the effect in 1522.
Q 30Which 1522 voyage first confirmed that circumnavigators lose a day?
Magellan–Elcano expedition
At Cape Verde the crew thought it was Wednesday 9 July; locals told them it was Thursday 10 July.