It's that time of year when it gets noticeable that the nights are drawing in. Here in London the sun sets about two minutes earlier every evening between the middle of August and the end of October (and a little slower at other times of year). That's about an hour a month, hence the inexorable creep towards winter darkness.
And this is why your local park closes at different times throughout the year.
This are the opening times for West Ham Park.
Opening the park is simple, someone comes round and opens up at 7.30am every morning (even in December when the sun's not quite up yet). But closing times vary considerably, with three winter months when closing time is 4.30pm and three summer months when closing time is 9.30pm. Someone in the Parks Department likes 'half past' because all the closing times are 'something thirty', which isn't necessarily a given.
Month
Sunset during month
Park closes
Jan
16:02 → 16:48
16:30
Feb
16:50 → 17:39
17:30
Mar
17:41 → 18:32
18:30
Apr
19:32 → 20:22
20:30
May
20:23 → 21:07
21:30
Jun
21:08 → 21:20
21:30
Jul
21:20 → 20:49
21:30
Aug
20:47 → 19:47
20:30
Sep
19:45 → 18:39
19:30
Oct
18:36 → 17:36
18:30
Nov
16:32 → 15:54
16:30
Dec
15:54 → 16:00
16:30
To keep things simple I've assumed that the clocks change at the very end of March and October, even though they don't quite.
The January closing time is roughly equivalent to the sunset time in the middle of the month, which might seem to make sense. But in most of the other months it's more towards the later end of the range, and in April, May, June, July and December the park always closes after sunset. The West Ham Park Parks Department are fairly generous with their locking-up times, well aware that it doesn't get properly dark for some time after the sun dips below the horizon. At least they've kept it simple.
This is Thames Barrier Park, and they're more premature.
This time opening up is always at 7.00am, even around Christmas when that's over an hour before sunrise. Closing time is a lot more complicated because they've only rounded to the quarter hour, and they've thrown BST into the mix for good measure. Also they've made me wag my finger in pedantic disapproval because you do not write PM with a 24-hour time, it's either 16:45 or 4.45PM, not both.
The Thames Barrier Park Parks Department are much better at aligning closing time to the sunset time in the middle of the month, as if that's how they used their almanac to determine when the gates should shut. November and December are the exceptions, with locking up taking place after sunset all month, but at the darkest time of year that temporal generosity is probably for the best.
The walkway alongside the Royal Albert Dock plays the game differently.
Unlocking is again at 7am but locking up occurs earlier than either of the two parks in every month of the year. Indeed it turns out that the Royal Albert Dock walkway always closes exactly half an hour earlier than Thames Barrier Park, as if the two have been precisely aligned.
Also they've made me wag my finger in genuine disapproval because they've used asterisks showing BST continuing into November and December, which is just sloppy, and they've described BST as British Standard Time, which is it not. A poor show, Royal Docks.
Month
Royal Docks
Thames Barrier
West Ham
Jan
16:15
16:45
16:30
Feb
17:00
17:30
17:30
Mar
18:00
18:30
18:30
Apr
19:30
20:00
20:30
May
20:15
20:45
21:30
Jun
20:45
21:45
21:30
Jul
20:30
21:00
21:30
Aug
20:00
20:30
20:30
Sep
18:45
19:15
19:30
Oct
17:45
18:15
18:30
Nov
16:15
16:45
16:30
Dec
16:00
16:30
16:30
Very roughly speaking Royal Albert Dock closing times generally align to the earliest sunset in a month, Thames Barrier Park closing times generally align to the average sunset in a month and West Ham Park closing times generally align to the latest sunset in a month. Given that twilight lingers after sunset I'd say West Ham Park has the most realistic closing times... and whoever knocked up the Royal Albert Dock list probably looked up sunset times online and didn't consider how light it actually is.
All of which proves very little other than that sunset-related closing times are quite subjective, perhaps much more so than you realised. And yes, sorry, they'll be locking up at least an hour earlier from Wednesday onwards.
