Network News

X My Profile
View More Activity
The new Washington
Post Weather website
Jump to CWG's
Latest Full Forecast
Outside now? Radar, temps
and more: Weather Wall
Follow us on Twitter (@capitalweather) and become a fan on Facebook
Posted at 10:45 AM ET, 03/16/2010

Daylight Saving changes time, not weather

By Ann Posegate

Wx and the City

* The sun has arrived and is here to stay: Full Forecast *

On early Sunday morning, most of the United States, save Hawaii and most of Arizona, sprung an hour ahead to Daylight Saving Time (DST), losing an hour of sleep in the process. However, when it came to weather observations and forecasting, the National Weather Service did not change its clocks this past weekend. Nor will it do so in November.

Hourly weather observations in locations throughout the world fit together like puzzle pieces, showing meteorologists the larger picture of what's going on in Earth's atmosphere at any given time. If times changed twice a year, the records would be inconsistent.

Keep reading for more on DST, but first take this poll...

Instead, official weather observations (measurements of temperature, humidity, wind speed, precipitation, etc.) are recorded using Coordinated Universal Time (UTC), also known as "Zulu" time, which remains consistent throughout the year. UTC has largely replaced Greenwich Mean Time (GMT) as the time system used in science.

On weather forecasting maps and models, as well as satellite images, time is displayed in UTC, usually on a 24-hour clock. For those of us on the East Coast of the United States, Eastern Standard Time (EST, November to mid-March) is five hours behind UTC. Eastern Daylight Saving Time (EDT, mid-March to November) is four hours behind it. A map updated today at "1200Z" or "12:00 UTC" would be valid for "0800 EDT" or 8:00 a.m. (check out this chart and the current regional radar image for examples of the conversion).

Interested in learning more about DST? Here's a great resource.

By Ann Posegate  | March 16, 2010; 10:45 AM ET
Categories:  Education, Posegate, Wx and the City  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Forecast: The return of the sun....
Next: The death of a snowpack


Note: with DST, the most recent model runs become available one hour later than during the winter

Posted by: SteveT-CapitalWeatherGang | March 16, 2010 11:02 AM | Report abuse

I know I've commented about this before. The only sensible solution to this twice-a-year time madness is to stay on fast time all year. This country did it during WWII with no problem. But the couple of times it has been tried since created such a flap and furor. The Province of Saskatchewan stays on CST all year, which that far west is equivalent to MDT. Even though in the middle of their winter it's dark until after 9:00AM, everyone has adjusted and the kids get to school safely. If they can do it, we can too.

Posted by: RAB2 | March 16, 2010 11:15 AM | Report abuse

We should be adjusting schedules with the sun, not adjusting time. Noon was supposed to be when the sun was overhead. If you want more daylight during waking hours, get up earlier. Or just make EST -0400.

Posted by: MaltyCharacter | March 16, 2010 11:25 AM | Report abuse

"Zulu" does not spring ahead or fall back.

Generally the effect is like a case of jet lag once a year, particularly in the spring when one loses an hour. The most annoying effect, from my perspective, is that extra hour of darkness in the morning!
It's just like going back to Christmas in terms of wake-up time; unfortunately we can't get a month extra of snow as part of the deal!

Posted by: Bombo47jea | March 16, 2010 11:39 AM | Report abuse

I'd like to say I was on Zulu time. Sounds cool.

Posted by: Snowlover2 | March 16, 2010 11:44 AM | Report abuse

More light is good!

Posted by: Ian-CapitalWeatherGang | March 16, 2010 11:46 AM | Report abuse

True Hawaiian Standard Time (pre-World War II) was 1 1/2 hours behind the US West Coast (Pacific Standard Time). The US military couldn't deal with that, so Hawaiian Standard Time was changed to 2 hours behind PST during WW II. As a result, Hawaii is on half-Daylight Saving Time all year.

Suggestion: Split the difference between Standard and Daylight Saving Time. Move all mainland time zones 1/2 hour, and stay on that time all year. (EST would become -4 1/2 hours from UTC.)

Posted by: rlguenther | March 16, 2010 12:05 PM | Report abuse

The permanent switch to 1/2 hour between standard and DST is a good idea.

But it may cause difficulty in calculating time differences when communicating with and traveling to the rest the world, since most other timezones are adjusted by a full hour in relation to UTC.

I do like this idea, though.

Check out another idea at

Posted by: beccamikey2002 | March 16, 2010 2:13 PM | Report abuse

Agreed that we should be on DST all year. When it starts getting dark before 5 pm, it's not good for anyone.

Posted by: ryanem1 | March 16, 2010 3:41 PM | Report abuse

There are a few places in the world with an additional 1/2 hour time difference. The only one in North America is Newfoundland. From my own personal experience attempting to deal with it, it's not such a good idea.

Having the entire world on Zulu time might make sense, especially as our "global village" continues to connect ever more closely together. Won't happen in my lifetime.

Posted by: RAB2 | March 16, 2010 7:40 PM | Report abuse

In Texas, it never gets dark before 5. So year round DST isn't the best solution for every location. We need to figure out which time, DST or Standard would be best year round for each location.

Posted by: beccamikey2002 | March 17, 2010 9:54 AM | Report abuse

The comments to this entry are closed.

RSS Feed
Subscribe to The Post

© 2012 The Washington Post Company