MST
Mountain Standard Time
GMT -7
12am
3am
6am
9am
12pm
3pm
6pm
9pm
Puerto Rico
AST
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Compare MST time with San Juan time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Mountain Standard Time is 3 hours behind AST (Atlantic Standard Time)
5:00 am05:00 in MST is 8:00 am08:00 in San Juan, Puerto Rico

MST to San Juan call time
Best time for a conference call or a meeting is between 9am-2pm in MST which corresponds to 12pm-5pm in San Juan

5:00 am05:00 Mountain Standard Time (MST). Offset UTC -7:00 hours
8:00 am08:00 AST (Atlantic Standard Time) (San Juan, Puerto Rico). Offset UTC -4:00 hours

5:00 am05:00 MST / 8:00 am08:00 San Juan, Puerto Rico

MSTSan Juan, Puerto Rico
12am (midnight)3am
1am4am
2am5am
3am6am
4am7am
5am8am
6am9am
7am10am
8am11am
9am12pm (noon)
10am1pm
11am2pm
12pm (noon)3pm
1pm4pm
2pm5pm
3pm6pm
4pm7pm
5pm8pm
6pm9pm
7pm10pm
8pm11pm
9pm12am (midnight)
10pm1am
11pm2am
00:0003:00
01:0004:00
02:0005:00
03:0006:00
04:0007:00
05:0008:00
06:0009:00
07:0010:00
08:0011:00
09:0012:00
10:0013:00
11:0014:00
12:0015:00
13:0016:00
14:0017:00
15:0018:00
16:0019:00
17:0020:00
18:0021:00
19:0022:00
20:0023:00
21:0000:00
22:0001:00
23:0002:00

Mountain Standard Time

Offset: MST is 7 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Canada, Mexico, United States

Principal Cities: The largest city in the MST time zone is Phoenix in the United States, with about 1.446 million people. Other major cities in this time zone include Calgary, Edmonton, El Paso, Denver.

French: HNR - Heure Normale des Rocheuses

Spanish: MT - Zona Pacífico

MST Time Zone Geo Map
MST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Mountain Daylight Time (MDT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Mountain Standard Time (MST) started on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Mountain Standard Time (MST) ends on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the second Sunday of March.

MST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -07 - basic short
  • -0700 - basic
  • -07:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0700 - sign character (-) followed by a four digit time providing hours (07) and minutes (00) of the offset. Indicates an offset of seven hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Tango - Military abbreviation for MST
  • T - short form of 'Tango'
IANA/Olson: Reflects MST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Boise
  • America/Cambridge_Bay
  • America/Ciudad_Juarez
  • America/Creston
  • America/Dawson
  • America/Dawson_Creek
  • America/Denver
  • America/Edmonton
  • America/Fort_Nelson
  • America/Hermosillo
  • America/Inuvik
  • America/Mazatlan
  • America/Phoenix
  • America/Shiprock
  • America/Whitehorse
  • America/Yellowknife
  • Canada/Mountain
  • Canada/Yukon
  • MST
  • MST7MDT
  • Mexico/BajaSur
  • Navajo
  • US/Arizona
  • US/Mountain
Time zones with the GMT -7 offset:
  • MST - Mountain Standard Time
  • PDT - Pacific Daylight Time
  • YST - Yukon Standard Time
  • T - Tango Time Zone

San Juan Information

Time Zone

Abbreviation / Name
AST - Atlantic Standard Time
UTC / GMT Offset
-4:00 hours during Atlantic Standard Time, currently in use.

San Juan Facts

Country
Puerto Rico
Alternative Names
Caparra, Ciudad de Puerto Rico, Portorico, Prico, Puerto Rico, SJU, Saint Iuan, Saint John de Porto Rico, Sainte Jean de Porto-rico, San Chouan, San Chuanas, San Huan, San Ian de Porto Rico, San Ioanni, San Jean de Portorico, San Juan, San Juan Batista de Puerto Rico, San Juan Bautistade de Puerto Rico, San Juan de Puerto Rico, San Khuan, San Xoan, San Xoán, San Xuan, San-Juano, San-Khuan, Sanhuana, The City of Saint John, Ville de Porto-Rico, Ville de Sainte Jean de Porto Rico, can van, saenhwan, san hwn, san khwan, san-khuani, sana hu'ana, sana huraana, sanfuan, sanhuan, sheng hu an, Σαν Χουάν, Сан Хуан, Сан-Хуан, Սան Խուան, סן חואן, سان خوآن, سان خوان, सान हुआन, সান হুৱান, ਸਾਨ ਹੁਆਨ, சான் வான், ซานฮวน, სან-ხუანი, サンフアン, 圣胡安, 산후안, 샌환
Population
418,140
Currency
Dollar (USD)
Geographic Coordinates
18° 27' N Latitude / 66° 06' W Longitude