diamond geezer

 Sunday, November 04, 2018

Today's the day that sunset in London slips over from "nearer 5pm" to "nearer 4pm". Yesterday the sun set at 4.31pm, and today it's 4.29pm. Sunset then remains "nearer 4pm" through the winter solstice and out the other side, until 21st January. Sorry, that's 11 weeks.

I can do similar calculations for "nearer 6pm", "nearer 7pm", "nearer 8pm" and "nearer 9pm", again all for London. Dates are for the next twelve months. Greenwich Mean Time is in blue, and British Summer Time is in red.

Nearer 4pm4 Nov - 21 Jan
Nearer 5pm22 Jan - 23 Feb27 Oct - 3 Nov
Nearer 6pm24 Feb - 30 Mar5 Oct - 26 Oct
Nearer 7pm 9 Sep - 4 Oct
Nearer 8pm31 Mar - 5 May12 Aug - 8 Sep
Nearer 9pm6 May - 11 Aug

"Nearer 6pm" is a GMT thing in the spring, but a BST thing in the autumn, because the dates we change the clocks aren't symmetrical. More intriguingly, "nearer 7pm" only happens in the autumn, and gets skipped over in the spring. In southeast England, 7pm sunsets are a September thing. Meanwhile we only get one week of 5pm sunsets in the autumn (it's just finished), but a full month of them later in the winter.

Let's do weeks.

Nearer 4pm11 weeks
Nearer 5pm6 weeks
Nearer 6pm8 weeks
Nearer 7pm4 weeks
Nearer 8pm9 weeks
Nearer 9pm 14 weeks

The time of sunset changes fastest at the equinoxes, and slows down at the solstices, which is why the largest numbers appear at the top and bottom of the table. British Summer Time very much messes up the pattern in the middle. But if you need something to hang onto during the next 11 dark weeks, remember that "nearer 9pm" lasts a good bit longer than "nearer 4pm".



Update: In response to a comment from a reader in the Orkney Islands, where the time of sunset ranges from 3.14pm to 10.28pm, here's the Orkney data.

Nearer 3pm6 weeks
Nearer 4pm8 weeks
Nearer 5pm4 weeks
Nearer 6pm6 weeks
Nearer 7pm4 weeks
Nearer 8pm6 weeks
Nearer 9pm7 weeks
Nearer 10pm 12 weeks



Update: A reader points out that Orkney is further west than London as well as a lot further north, making sunset a little later even before taking latitude into account. So here's the data for Newport, Wales, which has the same latitude as London but the same longitude as Orkney.

 London
51½°N 0°W
Newport
51½°N 3°W
Orkney
59°N 3°W
Nearer 3pm  6 weeks
Nearer 4pm11 weeks9 weeks8 weeks
Nearer 5pm6 weeks7 weeks4 weeks
Nearer 6pm8 weeks7 weeks6 weeks
Nearer 7pm4 weeks5 weeks4 weeks
Nearer 8pm9 weeks8 weeks6 weeks
Nearer 9pm 14 weeks13 weeks7 weeks
Nearer 10pm 3 weeks12 weeks



Update: A reader asks what the underlying pattern is, i.e. what the data would look like if we didn't put the clocks forward and stuck to GMT all year round. Here's London, GMT.

Nearer 4pm11 weeks
Nearer 5pm9 weeks
Nearer 6pm9 weeks
Nearer 7pm9 weeks
Nearer 8pm 14 weeks



Update: I was expecting sunrise times to look similar but, because we yank them in the opposite direction when the clocks change, the spread looks very different. Here's sunrise in London.

Nearer 5am14 weeks
Nearer 6am13 weeks
Nearer 7am14 weeks
Nearer 8am 11 weeks



Update: A reader has opened up the can of worms relating to what would happen if we no longer put the clocks back, i.e sticking to GMT+1 throughout the year. This is what'd happen to sunrise and sunset in London.

Nearer 5am14 weeks
Nearer 6am9 weeks
Nearer 7am9 weeks
Nearer 8am9 weeks
Nearer 9am 11 weeks
       
Nearer 5pm11 weeks
Nearer 6pm9 weeks
Nearer 7pm9 weeks
Nearer 8pm9 weeks
Nearer 9pm 14 weeks



Update: Another reader mentions Singapore, which lies one degree north of the equator. Here the maximum difference in sunset times is only thirty minutes, the earliest being in November (6.50pm, today!) and the latest in February (7.20pm). Reasons for this are complicated.

Nearer 7pm 52 weeks

n.b. Geography dictates that Singapore's time zone should be GMT+7, whereas in fact it adheres to GMT+8 to match Malaysia, China and the Philippines, which is why sunset is always nearer 7pm than 6pm.


<< click for Newer posts

click for Older Posts >>


click to return to the main page


...or read more in my monthly archives
Jan18  Feb18  Mar18  Apr18  May18  Jun18  Jul18  Aug18  Sep18  Oct18
Jan17  Feb17  Mar17  Apr17  May17  Jun17  Jul17  Aug17  Sep17  Oct17  Nov17  Dec17
Jan16  Feb16  Mar16  Apr16  May16  Jun16  Jul16  Aug16  Sep16  Oct16  Nov16  Dec16
Jan15  Feb15  Mar15  Apr15  May15  Jun15  Jul15  Aug15  Sep15  Oct15  Nov15  Dec15
Jan14  Feb14  Mar14  Apr14  May14  Jun14  Jul14  Aug14  Sep14  Oct14  Nov14  Dec14
Jan13  Feb13  Mar13  Apr13  May13  Jun13  Jul13  Aug13  Sep13  Oct13  Nov13  Dec13
Jan12  Feb12  Mar12  Apr12  May12  Jun12  Jul12  Aug12  Sep12  Oct12  Nov12  Dec12
Jan11  Feb11  Mar11  Apr11  May11  Jun11  Jul11  Aug11  Sep11  Oct11  Nov11  Dec11
Jan10  Feb10  Mar10  Apr10  May10  Jun10  Jul10  Aug10  Sep10  Oct10  Nov10  Dec10 
Jan09  Feb09  Mar09  Apr09  May09  Jun09  Jul09  Aug09  Sep09  Oct09  Nov09  Dec09
Jan08  Feb08  Mar08  Apr08  May08  Jun08  Jul08  Aug08  Sep08  Oct08  Nov08  Dec08
Jan07  Feb07  Mar07  Apr07  May07  Jun07  Jul07  Aug07  Sep07  Oct07  Nov07  Dec07
Jan06  Feb06  Mar06  Apr06  May06  Jun06  Jul06  Aug06  Sep06  Oct06  Nov06  Dec06
Jan05  Feb05  Mar05  Apr05  May05  Jun05  Jul05  Aug05  Sep05  Oct05  Nov05  Dec05
Jan04  Feb04  Mar04  Apr04  May04  Jun04  Jul04  Aug04  Sep04  Oct04  Nov04  Dec04
Jan03  Feb03  Mar03  Apr03  May03  Jun03  Jul03  Aug03  Sep03  Oct03  Nov03  Dec03
 Jan02  Feb02  Mar02  Apr02  May02  Jun02  Jul02 Aug02  Sep02  Oct02  Nov02  Dec02 

eXTReMe Tracker
jack of diamonds
Life viewed from London E3

» email me
» follow me on twitter
» follow the blog on Twitter
» follow the blog on RSS

my flickr photostream