Venezuela has pushed its clocks forward a half hour to save power.
President Nicolas Maduro ordered the change to deal with the country's chronic shortage of electricity.
Jorge Arreaza, Venezuela's science and technology minister, said the change will reduce the night-time use of lighting and air conditioning.
The government has initiated a packet of changes designed to save electricity, including rolling blackouts, a two-day public sector work week, and schools closed on Fridays.
Venezuela is now four hours behind Greenwich Mean Time.
All the changes come as Venezuela is experiencing a crushing recession.
The oil-rich country was once awash in money, but oil prices have fallen and so have the fortunes of Venezuela.
Maduro increased the minimum wage Sunday, but critics say rampant inflation makes it worthless.
Meanwhile, Maduro is facing calls for his ouster. The opposition says it has two million signatures on a petition from people who want the president removed from office.