Losing sleep over Daylight Savings Time

You’d think, after being married to a Navy guy for so many years, I’d know military time jargon by now. But when my husband, Francis, tells me he’s got a dentist appointment at “sixteen-thirty,” I start counting on my fingers and mumbling, “Subtract two …”

Although I did manage to memorize Francis’ social security number (it’s seared into my psyche like a tattoo), I’ve never been one of those military spouses who internalized acronyms and military idioms. To this day, I still get confused.

This Sunday, Daylight Savings Time (DST) begins, which further complicates time-telling for military folks. DST sounds simple — sets the clocks forward one hour in March and back one hour in November to take advantage of early daylight. We pronounce “spring forward, and fall back” as if we’re reading from a rudimentary Dick and Jane book, but in reality, calculating time in different parts of the world is a mind-boggling task when you take into account time zones, local time, universal time, solar time, longitude, and the tilt of the Earth’s axis.

To start, only 48 of the 50 states recognize DST. Hawaii, Arizona, and the US’s tropical territories don’t change clocks. However, Navajo Americans on native reservations in Arizona use DST. Go figure.

Most industrialized nations recognize DST, but the majority of the world’s population do not, since China, India and most countries in Africa never change clocks. Conversely, Argentina, Chile, Iceland, Singapore, Uzbekistan, Belarus, Turkey and Northern Cyprus use DST year-round.

Add to that quagmire the 25 time zones across the world, each one based on Greenwich Mean Time (GMT). Greenwich, England, a suburb of London, happens to be zero degrees longitude and has a royal observatory that tracks the position of the sun. Noon GMT is when the sun is directly over the Greenwich meridian, but since the Earth’s rotational variables cause discrepancies, GMT noon is the annual average of those times. Struggling to wrap your brain around GMT? Don’t bother, because Coordinated Universal Time (which, for reasons too complicated to explain here, is abbreviated as “UTC” rather than “CUT”) has replaced GMT as the primary standard for world time. UTC is more precise than GMT (although it is criticized for including “leap seconds” — don’t ask) and has been recognized since 1960 as the true basis from which all time is calculated.

GMT and UTC start with Z or Zulu time zone, with 12 zones to the east, and 12 to the west, ending at the International Date Line in the Pacific Ocean. For every time zone east of Zulu, an hour is added. For every time zone west of Zulu, an hour is subtracted.

But brace yourself, because in the zones on either side of the International Date Line, time is exactly the same, only one day apart. Which means that if there were two different boats floating on either side of the International Date Line within sight of each other, it can be noon on Monday in one boat, and noon on Tuesday in the other.

*BOOM*

If your brain hasn’t exploded by now, consider that the US military uses a 24-hour scale for local time zones, using DST where recognized (ex., 3:30 pm = 1530), but uses a 24-hour scale for Zulu time for operational communications across time zones. For example, the time to begin an airstrike might be communicated as 1850Z, which is 6:50 pm UTC. Which, by the way, is 1:50 pm Eastern Standard Time, unless it is Daylight Savings Time, which will make it 12:50 pm Eastern Standard Time.

Make sense? I didn’t think so.

So, this Sunday, if you are stationed in Germany which recognizes DST, and your spouse is on a ship somewhere off the coast of Japan, which doesn’t recognize DST, and you agree to call each other at exactly 6:00 pm Eastern Standard Time, then what time should you make the call?

I have no flipping clue. I would recommend calling every five minutes until someone picks up. Or just send an email.

There is only one thing I know for certain: At O-dark-thirty on Sunday, I’ll be losing an hour of sleep.