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America/Boise time zone

7:01AMMST

MSTUTC−7−2 h vs New York (you)

About America/Boise

America/Boise is the IANA time zone for Mountain: ID (south), OR (east) in United States. It currently keeps Mountain Standard Time (MST, UTC−7) in winter and Mountain Daylight Time (MDT, UTC−6) in summer.

Its principal location is Boise at 43.61° N, 116.20° W.

Abbreviations in use: MST, MDT. Offset page: UTC−7.

Rule for future years (POSIX TZ string)

MST7MDT,M3.2.0,M11.1.0

The standard time is called MST and is UTC−7. POSIX writes the offset with the opposite sign (west of Greenwich is positive), which is why the string says "7". Daylight saving time is called MDT and is UTC−6. It starts on the second Sunday of March at 02:00 and ends on the first Sunday of November at 02:00, local time. Software that has no full tzdata copy, such as many embedded devices, can use this string directly as the TZ environment variable.

Upcoming transitions

Computed from tzdata 2026f; local times are read on the clock just before each change.

History of America/Boise since 1970

The record starts with local mean time (UTC−7:45), which ended on November 18, 1883. The first daylight saving time in the record is in 1918.

YearsClocksAbbreviations
1970 onwardUTC−7 in winter, UTC−6 in summerMST, MDT

Before 1970

14 offset changes before 1970 in the record:

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/Cambridge_Bay, America/Ciudad_Juarez, America/Denver.

Places on America/Boise

Convert Boise time

Tip: Alt+↑/↓ steps the time by 15 minutes (Shift: one hour). The link keeps the date, time and direction.

Using America/Boise 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/Boise' })

# Python 3.9+
from zoneinfo import ZoneInfo
from datetime import datetime
datetime.now(ZoneInfo('America/Boise'))

// Java
java.time.ZonedDateTime.now(java.time.ZoneId.of("America/Boise"))

// Go
loc, _ := time.LoadLocation("America/Boise")
time.Now().In(loc)

-- PostgreSQL
SELECT now() AT TIME ZONE 'America/Boise';

# Shell
TZ='America/Boise' date

Platforms 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.

Questions

What is the UTC offset of America/Boise?
UTC−7 in winter and UTC−6 in summer (daylight saving time from the second Sunday of March at 2:00 AM to the first Sunday of November at 2:00 AM).
Does America/Boise observe daylight saving time?
Yes: clocks move one hour forward on the second Sunday of March at 2:00 AM and back on the first Sunday of November at 2:00 AM.
Which countries use America/Boise?
United States, according to zone1970.tab in tzdata.

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