The military time zone S ("Sierra") is UTC−6. A time in this zone is written with the letter as a suffix, for example 1221S.
America/Bahia Banderas (CST)America/Belize (CST)America/Boise (MDT)America/Cambridge Bay (MDT)America/Chihuahua (CST)America/Ciudad Juarez (MDT)America/Costa Rica (CST)America/Denver (MDT)America/Edmonton (MDT)America/El Salvador (CST)America/Guatemala (CST)America/Inuvik (MDT)America/Managua (CST)America/Merida (CST)America/Mexico City (CST)America/Monterrey (CST)America/Regina (CST)America/Swift Current (CST)America/Tegucigalpa (CST)MST7MDT (MDT)Pacific/Galapagos
| City | Local time | Difference from Sierra (S) |
|---|---|---|
| New York | Thu | 4 hours behind |
| Los Angeles | Thu | 7 hours behind |
| London | Thu | 1 hour ahead |
| Paris | Thu | 2 hours ahead |
| Dubai | Thu | 4 hours ahead |
| Mumbai | Thu | 5.5 hours ahead |
| Singapore | Fri | 8 hours ahead |
| Tokyo | Fri | 9 hours ahead |
| Sydney | Fri | 10 hours ahead |
| Johannesburg | Thu | 2 hours ahead |
| São Paulo | Thu | 3 hours behind |
| Chicago | Thu | 5 hours behind |
Sierra (S) is the NATO letter for UTC−6. Military and aviation messages write a time in this zone as four digits plus the letter, for example 0900S for 09:00 at UTC−6.
Civil time zones on UTC−6 right now include America/Bahia Banderas, America/Belize, America/Boise, America/Cambridge Bay, America/Chihuahua, America/Ciudad Juarez, America/Costa Rica, America/Denver.
| Mon | Tue | Wed | Thu | Fri | Sat | Sun |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | |||
| 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| 12 | 13 | 14 | 15 | 16 | 17 | 18 |
| 19 | 20 | 21 | 22 | 23 | 24 | 25 |
| 26 | 27 | 28 | 29 | 30 | 31 |