Until the nineteenth century, each country defined its own standard, which was generally based on the passage of the sun from its national observatory. The method was partially accurate, but it was not uncommon for clocks in nearby cities within the same country to mark different times. This was exacerbated by the popularization of European rail transport at the time. With “shorter” distances, the variation between times was even more keenly felt.
It was then that, in 1884, representatives from 25 countries gathered in Washington and decided that the Greenwich Meridian in England would become the global point of reference. As a result, the earth was divided into 24 sections 15° latitude apart, each marking an hour.
It was almost 40 years before this standard was adopted in Brazil. Prior to 1913, Recife celebrated New Year 33 minutes before São Paulo and one hour and five minutes after Porto Alegre.
Read the full article on the Super Interessante website.