Houston Military Time (24-Hour Clock)

What Is Military Time?

Military time uses the 24-hour clock format, running from 0000 (midnight) to 2359 (11:59 PM). It eliminates AM/PM confusion and is used worldwide by the military, aviation, healthcare, emergency services, and international business.

In Houston, military time follows the same 24-hour format. 1300 means 1:00 PM, 0700 means 7:00 AM, and 0000 is midnight.

How to Read Military Time — Beginner's Guide

If you're new to the 24-hour clock, here's a simple rule: for any time after 12:59 PM, subtract 12 to get the standard time. For example, 1500 minus 12 = 3:00 PM. Going the other way, add 12 to any PM time to get military time: 3:00 PM + 12 = 1500.

Key rules for reading military time:

• 0000–0059: 12:00 AM – 12:59 AM (midnight hour)
• 0100–1159: Same as standard time, just drop the colon (0900 = 9:00 AM)
• 1200–1259: 12:00 PM – 12:59 PM (noon hour)
• 1300–2359: Subtract 12 to get PM time (1730 = 5:30 PM)

Military time is spoken differently too: 0900 is "zero nine hundred," 1430 is "fourteen thirty," and 0015 is "zero zero fifteen." In Houston, you'll hear military time at NASA, in hospitals, and at the airports.

Houston Military Time and Zulu Time

Zulu time (designated by the letter "Z") is the military designation for UTC/GMT. Houston's military time zone letter is "R" (Romeo — CDT/UTC−5). To convert Houston local military time to Zulu, add 5 hours.

For example, if it's 1400 Houston time (CDT), Zulu time is 1900Z. If the result exceeds 2400, subtract 2400 and move to the next day. So 2200 Houston time becomes 0300Z the following day.

Who Uses Military Time in Houston?

• NASA / Johnson Space Center: Mission control uses UTC (Zulu) for all operations
• Houston airports (IAH, HOU): Aviation uses Zulu time for scheduling and ATC
• Texas Medical Center: 24-hour clock for patient records and medication schedules
• Energy industry: Global operations coordinate using UTC timestamps
• US military installations: Ellington Field and other bases use military time
• Emergency services: HPD, HFD, and EMS dispatch all use 24-hour time
• International shipping: Port of Houston uses UTC for vessel tracking

Military Time Zone Letters

The military assigns a letter to each time zone. Houston uses R (Romeo). Here are the most relevant to Houston:

• Z (Zulu): UTC+0 — The universal reference (GMT)
• R (Romeo): UTC−5 — Houston during CDT (summer)
• S (Sierra): UTC−6 — Houston during CST (winter)
• Q (Quebec): UTC−4 — Atlantic Time
• T (Tango): UTC−7 — Mountain Time
• U (Uniform): UTC−8 — Pacific Time

Related Pages

See current Houston time, convert Houston time to GMT, view the world time zone map, or use our time zone converter.