BRT — Brasilia Time

Brasilia Time (BRT) is three hours behind Coordinated Universal Time and is the standard time used in eastern Brazil, including the capital Brasilia, Sao Paulo, Rio de Janeiro, and most of the country's major population centers. It is named after Brasilia, the national capital, and is the most widely used of Brazil's four time zones. Sao Paulo, the largest city in the Southern Hemisphere, operates on BRT.

Brazil spans four time zones from UTC-2 (Atlantic islands) to UTC-5 (Acre state), but BRT covers the vast majority of the population and economic activity. The Sao Paulo Stock Exchange (B3) is the largest in Latin America and operates on Brasilia Time, making it the reference time for Brazilian commerce. BRT is also used by French Guiana, the Falkland Islands, and parts of Greenland.

Brazil has had a turbulent history with daylight saving time. The country observed DST from 1931 onward with various interruptions, but in 2019 President Bolsonaro abolished the practice entirely, citing studies that showed minimal energy savings and public dissatisfaction. Since then, BRT has remained at UTC-3 year-round across all regions that previously observed DST.