End of daylight saving means end of dark mornings

End of daylight saving means end of dark mornings

Published by Nick Lomb on April 1, 2014 4 Comments

Sunrise times_Sydney_2014_Nick Lomb

Graph indicating sunrise in Sydney throughout the year. It is calculated for 2014 but there is little change from year to year except for the slight shift of the starting and ending dates for daylight saving. Diagram Nick Lomb

If you rise early whether for work, school, gym, a run or walking the dog you are probably sick of the dark mornings that crept up on us very quickly in recent weeks. In that case, help is at hand for this coming Sunday (6 April 2014) is the first Sunday in April and hence daylight saving finishes early that morning.

As can be seen on the above graph the morning before, that is, Saturday morning, is the latest sunrise for the year with the Sun rising at 7:10 am. In the depths of winter at the end of June and the beginning of July the latest sunset is only 7:01 am. So the mornings may well become cooler as the year progresses towards winter, but it is not going to become darker.

If you think that 7:10 am is late for sunrise, spare a thought for the 8000 or so people of the small town of Wentworth in the south-west of NSW. The town is approximately 9° to the west of Sydney and, as each degree of longitude represents four minutes of time, sunrise occurs about 36 minutes later than in Sydney. There the latest sunrise for the year is on Saturday at 7:47 am.

Of course, some people may be disappointed by the earlier sunrise. If you are trying to sleep in for instance you may not appreciate being woken up by light spilling through edges and gaps in blinds and curtains. Also others may have enjoyed the opportunity to see the planet Venus and other objects in the dark morning sky such as passes by the International Space Station.

The above diagram is a useful one as we can see how daylight saving acts to reduce the spread of sunrise times throughout the year. Without daylight saving in early December sunrise would be as early as 4:37 am, which could be a serious difficulty for those trying to sleep at that time.

An interesting, just released, American study suggests that at the start of daylight saving in spring there is a spike of 25% in people experiencing heart attacks, presumably due to losing one hour’s sleep. Conversely, at the end of daylight saving in autumn when the clocks are moved backwards by an hour there is a 21% decrease in heart attacks. The study is based on data from only one American state and the authors suggest that it would be worthwhile comparing the results of their study with data from a state that does not have daylight saving. Maybe a comparison could be done in Australia between hospitals in Sydney and in Perth where there is no daylight saving?

If you like you can stay up till 3 am to change your clocks on Sunday morning. For most people though it is easier and more sensible to do so before going to bed on Saturday evening. And, fortunately, these days many devices like mobile phones, tablets and computers, tend to change automatically without the need for human intervention. However you do it, enjoy the extra hour of sleep on Sunday morning and the lighter mornings from then on.

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4 Responses to “End of daylight saving means end of dark mornings”

  1. April 02, 2014 at 1:27 pm, Andy said:

    Great graph! Are you also able to do one for sunset times? Thanks!

    Reply

    • April 02, 2014 at 4:17 pm, Nick Lomb said:

      Hello Andy. I am pleased that you like the graph as I think that it is most informative. For simplicity I did not do a graph of sunset times for the year this time, but I have done so on a previous blog post four years ago.

      Reply

  2. April 02, 2014 at 8:29 am, Roberto said:

    The fact that the latest sunrise for the year occurs in April rather than mid-winter just confirms for me that daylight saving lasts far too long. It used to end on the first Sunday in March, which makes far more sense.

    And regarding Broken Hill – doesn’t it use Australian central (Adelaide) time? So it’s latest sunrise would be closer to 7.18am.

    Reply

    • April 02, 2014 at 12:05 pm, Nick Lomb said:

      Hello Roberto. Oops! I had forgotten that Broken Hill keeps South Australian time. Thank you for pointing it out. I have now corrected the post to discuss the town of Wentworth instead. With regard to the dates of the start and ending of daylight saving I will just point out that the current arrangement is based on an agreement between NSW, Victoria, Tasmania, ACT and South Australia. Whatever minor difficulties there maybe with this arrangement going back to separate schemes in different states would be far worse.

      Reply

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