Technical Specifications & Standards
Official chronometric properties, ISO standards, and international database registry identifiers for Paraguay Summer Time:
Daylight Saving Time (DST) Transitions
⬆️ Spring Forward (Clocks Advance)
First Sunday in October at 24:00 / midnight (Clocks advance from PYT to PYST)
⬇️ Fall Back (Clocks Return)
Fourth Sunday in March at 24:00 / midnight (Clocks return from PYST to PYT)
Observing Jurisdictions & Subdivisions
1 Sovereign NationsSovereign nations, administrative subdivisions, and regional territories officially operating under PYST:
Regional Subdivisions & Territory Details
Financial Markets & Trading Hours
During southern summer, Paraguay matches clock time with São Paulo and Buenos Aires, creating unified trading hours across Mercosur partners.
Local Hours: 09:00 - 15:00 PYST
UTC Window: 12:00 - 18:00 UTC
Major Cities in PYST
Primary metropolitan centers and financial hubs observing this time zone:
Adoption History & Astronomical Facts
Year Established: 1975
Instituted regularly in the mid-1970s to match seasonal electricity demand from the Itaipu Dam, the binational hydroelectric giant co-owned with Brazil on the Paraná River.
Because Paraguay observes Daylight Saving Time while neighboring Brazil abolished it in 2019, Asunción and São Paulo share the exact same time throughout the southern summer months.
Frequently Asked Questions about PYST
What is the difference between PYST and PYT?
PYST (Paraguay Summer Time, UTC-3) is the daylight saving offset used between October and March. PYT (Paraguay Time, UTC-4) is the winter standard time observed between March and October.
Is Asunción ahead of New York during PYST?
Yes. During the Northern Hemisphere winter when New York uses EST (UTC-5), Asunción on PYST (UTC-3) is 2 hours ahead of New York.
What time does Paraguay change clocks?
Clocks advance by one hour at midnight (24:00) on the first Sunday in October, and turn back by one hour at midnight on the fourth Sunday in March.