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Posted at 12:59 PM ET, 11/02/2012

Daylight saving time ends November 4 as Northern Hemisphere enters darkest quarter of the year


Comparison of sunset times before and after daylight saving time ends on Nov. 4. (CWG, data from timeanddate.com)
As November begins, evening daylight is increasingly in short supply. Soon the sun will set even earlier as daylight saving time (DST) ends this Sunday. On November 4, we shift our clocks back one hour at 2 a.m. local time, which offers a welcome extra hour of sleep but also more evening darkness.

The good news, especially for early risers, will be brighter mornings next week. Currently, the sun doesn’t rise until 7:30 a.m. or later in many of the nation’s big cities.

Interestingly, ever since DST was extended in 2007, most locations in the lower 48 states now see their latest sunrises of the year in early November before the clocks “fall back.”


Comparison of sunrise times before and after daylight saving time ends on Nov. 4. (CWG, data from timeanddate.com)

That’s because with only seven more weeks until the winter solstice, there isn’t enough time for the sunrise time to regain the hour we set it back this weekend.

Only the northernmost tier of the continental U.S. – above 47ºN latitude – will see sunrise creep a full hour later between now and early January, which is when we see our latest sunrises while back on standard time (read why).

Those who prefer sunlit mornings will be pleased to know that even on our shortest day of the year, the mornings won’t be quite as dark as they are now. That’s good news for people with seasonal affective disorder or those who have trouble getting out of bed in the morning. On the other hand, if you lament driving home from work in the dark, the end of DST reminds us that the dark days of winter are ahead (in Washington, D.C., for instance, the sun will set before 5 p.m. from November 9 until January 4).

In fact, while most of us consider winter to begin sometime in December, solar winter – our darkest quarter of the year – already begins around November 5. Some ancient cultures actually defined winter as the darkest three months of the year: November through January. During this three-month period, the Northern Hemisphere receives the least amount of solar energy and more than half of the hemisphere is in darkness at any one time.

Whether you look forward to a bit more morning light or dread an extra hour of evening darkness, the onset of “solar winter” means that no matter how we shift our clocks, the days are getting too short to keep both early birds and night owls basking in the sun.

Related:

After the winter that wasn’t, time to spring ahead again

Daylight saving time: Why we change our clocks

By  |  12:59 PM ET, 11/02/2012

Categories:  Latest, Astronomy

 
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