Hi @Cinebar
At the moment in my game I am not too worried by darker nights as I use Criquette's neighborhood lights deco in all my streets on the map which might help your issue.
https://criquette-was-here.tumblr.com/post/157941587426/working-street-lights-hood-deco-set-ts2-quiet
If you like using Voeilles's water mod which I do then you will need Criquettes version of the neighborhood lights that is compatible with that creators water mod ( works on all ponds & the sea)
https://an-elegant-simblr.tumblr.com/post/155941049260/pond-sea-water-overhaul
this is an evening Pleasantview map view using Criquettes neighborhood lights (prior to sky mods)
https://i.imgur.com/Y4NIGWw.jpg
street/lot view evening no sky mods used
https://i.imgur.com/ODjHc8y.jpg
I used neighborhood lights externally next to my sims lot outdoors to show the lighting in the evening (sky mods used)
https://i.imgur.com/PUXqysI.jpg
here is a daytime view of clouds and water (using both sky and water mod)
https://i.imgur.com/gQtuAxe.jpg
This is the whole map view of the clouds meeting the edge of the map
https://i.imgur.com/QU2Ava5.jpg
Lastly if you want to add more light to your maps you can use a variety skyscraper lots and smaller residential styles of empty lots that are just deco but the lights come on at dusk until dawn. I don't have a pic of the smaller deco houses but these skyscraper lots show what I mean.
https://i.imgur.com/OBDuitv.jpg
19 lit-up nhood deco skyscrapers from “cities in motion” and “cities: skylines” for The Sims 2
deedee-sims also made some smaller neighborhood lots that light up at night
https://deedee-sims.tumblr.com/post/186404046232/in-todays-things-that-deedee-doesnt-need-in-her
https://lowedeus.tumblr.com/post/184053609941/emerald-city-19-lit-up-nhood-deco-skyscrapers-from
more here and I have used all these and they look fab in game
https://beautifulnerdkitty.tumblr.com/post/172940938359/4t2-neighbourhood-deco-included-three-color
I also Numenor's The SCRIPTORIUM: v. 2.2f (BugFix + Radiance 2.4) with GunMods lighting mod
http://modthesims.info/d/192613
If you don't want the Scriptorium you can separately download dDefinder's Gunmod's Radiance Light System 2.4 and upon reading the description it could be what you are looking for as it mentions various tweaks to indoor/outdoor lighting plus I know this is compatible with Criquette's neighborhood light deco as I use them both in my game. (once you have seen the neighborhood lights around the world you never want to go back-)
https://modthesims.info/download.php?t=290746
or this GunMod's Camera Mod 3.1 -- All Game Versions
https://modthesims.info/d/97642
I also use Nopke skyFix 2.1 this makes the stars brighter and I think the moon comes back into view. You need to read through and make sure everything is compatible however I use this with the neighborhood lights deco and the Gumods lighting mod along with scriptorium so there will be no issues using that particular combination.
I also use a compatible sky box to everything listed above that actually allows the stars to be shown through the atmosphere via Nopke's skyfix plus provide moving clouds (you can set the speed) which look awesome and if my memory serves the mod I use covers both the neighborhood map and lot view which saves an awful lot of work however I forget the exact mod so if you wanted to know about that one let me know and I will try find out which exact one it is because I have tried loads of them in the past-)
I am almost positive I am using these sky boxes put cannot tell you in what combination-) :)
https://lowedeus.tumblr.com/post/163111276336/every-july-we-celebrate-a-very-special-date
I probably went overboard but when I start a project lol :)
Edit Cyjon has a Outdoor Lights All Night mod but I have never tried it
http://cyjon.net/node/150
@thisfatfunnylife
Thanks for that link I had not seen that one before so I have saved the link to take a look :)