How Wrong Is Your Clock? Clock Time Against Solar Time for the World's People in 2026
Year: 2026
Type: preprint
Abstract: Clock time and solar time agree only along a few lines of longitude. Everywhere else the sun reaches its highest point before or after noon on the clock, and politics and daylight saving have moved most clocks further from the sun. I measure the gap between legal clock time and mean solar time for the world's population under the time zone rules of 2026, combining the timezone-boundary-builder boundaries (release 2026a), the IANA time zone database (2026e), Kontur's 22 km population hexagons and 148,692 GeoNames places of 1,000 people or more, with sunrise, sunset and solar noon from the NOAA solar equations for every day of the year. Averaged over 2026, 76% of the world's people live where the clock runs ahead of the sun, 33% by more than half an hour and 9.2% by more than an hour; only 1.7% live where it runs more than half an hour behind. Spain is the furthest ahead of 162 countries of a million people or more, at 1 h 44 min on average. In Galicia, at the western end of Spain's Central European clock, the latest sunrise of the year is 9:06 in A Coruña against 8:06 in London; among 590 European cities of 100,000 or more south of 55 degrees north, only Brest has a later winter sunrise. The largest gaps for big cities come from single national clocks: Kashgar runs 2 h 56 min ahead of the sun on Beijing time, and Tinsukia in Assam 51 min behind on India Standard Time. An interactive map gives the gap, sunrise, solar noon and sunset for any point through the year. Interactive version: https://maps.tristanhotham.com/clock-vs-sun/. Data and code: https://github.com/Tristan-Hotham/clock-vs-sun. Blog post: https://blog.tristanhotham.com/2026/10/28/clock-vs-sun/.
Author: Hotham, Tristan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7224607490