America/Rio_Branco time zone
8:43AMUTC−5
UTC−5UTC−5+0 h vs New York (you)
No transitions: America/Rio_Branco stays on UTC−5.
About America/Rio_Branco
America/Rio_Branco is the IANA time zone for Acre in Brazil. It currently keeps UTC−5 all year.
Its principal location is Rio Branco at 9.97° S, 67.80° W.
Rule for future years (POSIX TZ string)
<-05>5
The standard time is called “-05” (a numeric abbreviation) and is UTC−5. POSIX writes the offset with the opposite sign (west of Greenwich is positive), which is why the string says "5". There is no daylight saving rule: the zone stays on this offset for every year after the end of its explicit transitions. Software that has no full tzdata copy, such as many embedded devices, can use this string directly as the TZ environment variable.
History of America/Rio_Branco since 1970
The record starts with local mean time (UTC−4:31), which ended on January 1, 1914. The first daylight saving time in the record is in 1931.
| Years | Clocks | Abbreviations |
|---|---|---|
| 1970–1984 | UTC−5 all year | — |
| 1985 | UTC−5 until November 2, then UTC−4 | — |
| 1986–1987 | UTC−5 in winter, UTC−4 in summer | — |
| 1988 | UTC−4 until February 7, then UTC−5 | — |
| 1989–2007 | UTC−5 all year | — |
| 2008 | UTC−5 until June 24, then UTC−4 | — |
| 2009–2012 | UTC−4 all year | — |
| 2013 | UTC−4 until November 10, then UTC−5 | — |
| 2014 onward | UTC−5 all year | — |
Before 1970
23 offset changes before 1970 in the record:
- Thursday, January 1, 1914: UTC−4:31 → UTC−5
- Saturday, October 3, 1931: UTC−5 → UTC−4, daylight saving time
- Friday, April 1, 1932: UTC−4 → UTC−5
- Monday, October 3, 1932: UTC−5 → UTC−4, daylight saving time
- Saturday, April 1, 1933: UTC−4 → UTC−5
- Thursday, December 1, 1949: UTC−5 → UTC−4, daylight saving time
- Sunday, April 16, 1950: UTC−4 → UTC−5
- Friday, December 1, 1950: UTC−5 → UTC−4, daylight saving time
- Sunday, April 1, 1951: UTC−4 → UTC−5
- Saturday, December 1, 1951: UTC−5 → UTC−4, daylight saving time
- Tuesday, April 1, 1952: UTC−4 → UTC−5
- Monday, December 1, 1952: UTC−5 → UTC−4, daylight saving time
- Sunday, March 1, 1953: UTC−4 → UTC−5
- Monday, December 9, 1963: UTC−5 → UTC−4, daylight saving time
- Sunday, March 1, 1964: UTC−4 → UTC−5
- Sunday, January 31, 1965: UTC−5 → UTC−4, daylight saving time
- Thursday, April 1, 1965: UTC−4 → UTC−5
- Wednesday, December 1, 1965: UTC−5 → UTC−4, daylight saving time
- Tuesday, March 1, 1966: UTC−4 → UTC−5
- Tuesday, November 1, 1966: UTC−5 → UTC−4, daylight saving time
- Wednesday, March 1, 1967: UTC−4 → UTC−5
- Wednesday, November 1, 1967: UTC−5 → UTC−4, daylight saving time
- Friday, March 1, 1968: UTC−4 → UTC−5
Changes of the winter (standard) offset: Tuesday, June 24, 2008, UTC−5 → UTC−4; Sunday, November 10, 2013, UTC−4 → UTC−5.
tzdata commits to accuracy from 1970 for every zone (zone1970.tab); earlier entries are historical research and may be incomplete.
Aliases and zones with the same clock
These older or country-specific IDs are links to America/Rio_Branco in tzdata. Their pages redirect here: America/Porto_Acre, Brazil/Acre.
Other zones that keep exactly the same time under the current rules (but have a different history): America/Bogota, America/Cancun, America/Eirunepe, America/Guayaquil, America/Jamaica, America/Lima, America/Panama, America/Winnipeg.
Convert Rio Branco time
Using America/Rio_Branco in code
Every major platform reads the same IANA ID. Store instants in UTC and convert with the ID at display time; never store a fixed offset for a place that has daylight saving time.
// JavaScript
new Date().toLocaleString('en-US', { timeZone: 'America/Rio_Branco' })
# Python 3.9+
from zoneinfo import ZoneInfo
from datetime import datetime
datetime.now(ZoneInfo('America/Rio_Branco'))
// Java
java.time.ZonedDateTime.now(java.time.ZoneId.of("America/Rio_Branco"))
// Go
loc, _ := time.LoadLocation("America/Rio_Branco")
time.Now().In(loc)
-- PostgreSQL
SELECT now() AT TIME ZONE 'America/Rio_Branco';
# Shell
TZ='America/Rio_Branco' datePlatforms ship their own copy of tzdata and update it on their own schedule. After a rule change, outputs can differ until the platform updates; this page uses tzdata 2026f.