America/Cuiaba time zone
10:38AMUTC−4
UTC−4UTC−4+1 h vs New York (you)
No transitions: America/Cuiaba stays on UTC−4.
About America/Cuiaba
America/Cuiaba is the IANA time zone for Mato Grosso in Brazil. It currently keeps UTC−4 all year.
Its principal location is Cuiaba at 15.58° S, 56.08° W.
Rule for future years (POSIX TZ string)
<-04>4
The standard time is called “-04” (a numeric abbreviation) and is UTC−4. POSIX writes the offset with the opposite sign (west of Greenwich is positive), which is why the string says "4". 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/Cuiaba since 1970
The record starts with local mean time (UTC−3:44), which ended on January 1, 1914. The first daylight saving time in the record is in 1931.
| Years | Clocks | Abbreviations |
|---|---|---|
| 1970–1984 | UTC−4 all year | — |
| 1985 | UTC−4 until November 2, then UTC−3 | — |
| 1986–2002 | UTC−4 in winter, UTC−3 in summer | — |
| 2003 | UTC−3 until February 16, then UTC−4 | — |
| 2004 | UTC−4 until November 2, then UTC−3 | — |
| 2005–2018 | UTC−4 in winter, UTC−3 in summer | — |
| 2019 | UTC−3 until February 17, then UTC−4 | — |
| 2020 onward | UTC−4 all year | — |
Before 1970
23 offset changes before 1970 in the record:
- Thursday, January 1, 1914: UTC−3:44 → UTC−4
- Saturday, October 3, 1931: UTC−4 → UTC−3, daylight saving time
- Friday, April 1, 1932: UTC−3 → UTC−4
- Monday, October 3, 1932: UTC−4 → UTC−3, daylight saving time
- Saturday, April 1, 1933: UTC−3 → UTC−4
- Thursday, December 1, 1949: UTC−4 → UTC−3, daylight saving time
- Sunday, April 16, 1950: UTC−3 → UTC−4
- Friday, December 1, 1950: UTC−4 → UTC−3, daylight saving time
- Sunday, April 1, 1951: UTC−3 → UTC−4
- Saturday, December 1, 1951: UTC−4 → UTC−3, daylight saving time
- Tuesday, April 1, 1952: UTC−3 → UTC−4
- Monday, December 1, 1952: UTC−4 → UTC−3, daylight saving time
- Sunday, March 1, 1953: UTC−3 → UTC−4
- Monday, December 9, 1963: UTC−4 → UTC−3, daylight saving time
- Sunday, March 1, 1964: UTC−3 → UTC−4
- Sunday, January 31, 1965: UTC−4 → UTC−3, daylight saving time
- Thursday, April 1, 1965: UTC−3 → UTC−4
- Wednesday, December 1, 1965: UTC−4 → UTC−3, daylight saving time
- Tuesday, March 1, 1966: UTC−3 → UTC−4
- Tuesday, November 1, 1966: UTC−4 → UTC−3, daylight saving time
- Wednesday, March 1, 1967: UTC−3 → UTC−4
- Wednesday, November 1, 1967: UTC−4 → UTC−3, daylight saving time
- Friday, March 1, 1968: UTC−3 → UTC−4
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
Other zones that keep exactly the same time under the current rules (but have a different history): America/Barbados, America/Boa_Vista, America/Campo_Grande, America/Caracas, America/Guyana, America/La_Paz, America/Manaus, America/Martinique, America/Porto_Velho, America/Puerto_Rico, America/Santo_Domingo.
Convert Cuiaba time
Using America/Cuiaba 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/Cuiaba' })
# Python 3.9+
from zoneinfo import ZoneInfo
from datetime import datetime
datetime.now(ZoneInfo('America/Cuiaba'))
// Java
java.time.ZonedDateTime.now(java.time.ZoneId.of("America/Cuiaba"))
// Go
loc, _ := time.LoadLocation("America/Cuiaba")
time.Now().In(loc)
-- PostgreSQL
SELECT now() AT TIME ZONE 'America/Cuiaba';
# Shell
TZ='America/Cuiaba' 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.