Cities: Skylines

Cities: Skylines

175 ratings
Moon Phases
File Size
3.333 MB
Aug 25, 2016 @ 10:46am
Aug 26, 2016 @ 10:32am
3 Change Notes ( view )

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Moon Phases

A customizable moon cycle implementation

Use dynamic moon cycle, or pick your favorite moon texture and settings.

What does this mod do?

This mod is my attempt to add another layer of realism to Cities:Skylines by implementing a basic moon cycle(purely visual for now) into the game.

Current features:
  • 24 different moon phase textures.
  • Moon size slider.
  • Custom HD 4096px outer space cubemap based on HYG 3.0: Hipparcos, Yale Bright Star, and Gliese star data catalogs.
  • Automatic moon phase changes based on game date-time.
  • Automatic moonlight and outer space/stars brightness change depending on current phase. ie. dim stars and bright moonlight during full moon; bright stars and dim moonlight during new moon that progressively increase/decrease during cycle.
  • Option to set Static mode, which lets you pick your preferred moon, moonlight and outer space/stars brightness and have it stay that way indefinitely.
  • Option to have dynamically changing moon phase, but static moonlight and outer space/stars brightness.
  • Slick In-Game Option GUI that remembers its position on screen across sessions.
  • GUI Toggle button in Toolbar (Next to temperature panel).
  • Save your settings or reset them to mod default with the click of a button.
  • More to come! Stay tuned!

How does it work?

The mod loads its assets into memory right after you click the load button when starting/loading a city. It will add about 5 seconds to your loading times.

When the city finishes loading, the mod sets its custom cubemap, horizon color, brightness settings, etc, then checks the day of the year against its list of moon phase change dates, and sets the current moon phase accordingly. If you've previously set the mode to Static, this doesn't happen and instead your saved settings get loaded.

During game play on Dynamic mode, the mod detects when a phase change date has been reached, and updates the moon phase accordingly.

If you disable day-night cycle or it is currently day time in the game, the mod does nothing, so it shouldn't be taxing on resources at all. In fact I didn't notice any performance hit whatsoever even during night time with dynamic mode on.

Phase changes occur every ~15 game days, which means several times per "night".
What? Yes, the day/night cycle is independent of actual game days, as you might have noticed.

This is currently not customizable. If you think its too quick, please leave feedback and just use static mode for now.


It is incompatible with any mod that change the moon textures, outerspace cubemap textures, moonlight brightness, stars intensity, night horizon color, or moon coronas.

The only mod I know of which does any of that is:

This mod changes the night sky cubemap and as such it will conflict.
Please disable or unsubscribe from Skyscapes 1 if you are using it before using Moon Phases.

This mod is compatible with every other mod, including Map Themes which will simply have their moon textures and night colors settings overwritten by Moon Phases.

Mods that complement Moon Phases

Ultimate Eyecandy

Use Ultimate Eyecandy to help you achieve your desired look/feel for your screenshots! It's a great mod, and I took a lot of my inspiration from it, as well as using it as a base to build my UI from. Thanks Judazzz!

I'd like to thank in no particular order: OWL for his valuable feedback about the GUI and its look. bloodypenguin for all the help he has provided to help me learn C#. boformer for providing a skeleton for my Terrain Themes mod from which I learned a great deal. Judazzz for his Ultimate Eyecandy mod from which I learned how to make a decent User Interface. SamSamTS for writing the original UI code from which Judazzz derived. AcidFire for writing the code which helped SamSamTS. (Yay for nested thank yous!) Colossal Order and Paradox Interactive for this great game.

Planned Features
  • Improve the moon textures(Help needed with this, if you're an animator or an artist and you're interested, contact me in the comments below) I'd love to have more phases and achieve a smooth animation effect, where the moon slowly waxes/wanes over time instead of the current "steps" it takes into the next phase.
  • Improve the outer space cubemap.
  • Add more cubemap options so you can pick your favorite sky.
  • Add alternative moon textures so you can pick yellowish/blueish moons, etc.
  • Ability to customize phase change frequency through options GUI or in xml file. Currently if you try to do anything like that through xml file you will break the mod: Don't do it.
  • Ability to change the night horizon color.
  • Ability to change the game stars brightness(currently game stars are disabled entirely, the ones you see are from outer space cubemap)
  • Have the moon phase influence the game in real ways; for example, tides and crime rate fluctuations.
  • Figure out how to make the moon render brighter.

Known Issues

Sometimes for some obscure reason this happens:

To fix it just increase the moon size until the white lines disappear, then save settings. Will try to find a definitive solution.



This is mod is entirely useless. Yes, you heard me right, it doesn't really *DO* anything, its only for eye candy, just visuals, for taking screenshots and such.

I am looking at the possibility of adding some meaningful aspects to it for future versions but as of now, its a pretty much useless exercise in modding and UI building. I did it because I was tired of always having a full moon and because I enjoy a challenge. If you don't like it, I totally understand you, feel free to not use it :)


I am not a professional programmer, as such, I cannot guarantee my code is optimal. I did my best with what I've learned so far to make the mod as lightweight as possible. If you do notice any performance issues, please let me know in the comments below and I will do my best to address them.


If you have any ideas to improve this mod, please let me know in the comments below, or feel free to start an Ideas discussion.

If you have bugs to report please use pastebin and post a link. DON'T paste your output log to a comment.

If you want your sky to look like in the Screenshot, you need Ultimate Eyecandy and disable LUT color correction.
Otherwise its not as black.

This mod is licensed under a MIT License (MIT)[]

Enjoy! (rate+fav if you like it : )

If you're feeling generous and would like to buy me the morning paper or a drink, you can donate using the link below.

All donations are extremely appreciated. They are a great incentive for me to continue working on Mods in the future.

Thank you!

< >
pmisson Jul 12 @ 5:24pm 
Hi, I really love this mode. But the new moon nights still too bright and there is shows that follow the non existing moon. It would be great if that could be fixed. I don't know why but before was working better.
Bruggenbouwer Jul 10 @ 1:16am 
@aubergine18 that's a vanilla effect, this mod doesn't change it
aubergine18 Jul 5 @ 8:19am 
Is there a way to alter the aurora effects? My favorite boreal map seems to have aurora almost every night which is a bit overkill :/
benzoll Jun 29 @ 2:22am 
Work in v1.10 :hardhat:
Unknown_Soldier408sj Jun 1 @ 2:18am 
is this mod uptodate and comp. with parklife? mostly wondering if this mod is uptodate.. thanks
T​​​P​​​B  [author] Feb 26 @ 4:52am 
Added to my modding to-do list. (I am unlikely to do it anytime soon though as I am busy irl)
Haz Feb 13 @ 1:38pm 
Any chance you can allow us to move the button? I am using a custom UI and your button is just right in the middle of one of the panels. I tried editing the PanelPosition.xml but that doesn't appear to do anything
SleweD Sep 30, 2017 @ 9:31am 
Is there a way to make the moon itself brighter in the sky? It's working great but I can't actually see the moon most of the time since it's dark.
T​​​P​​​B  [author] Sep 10, 2017 @ 1:06pm 
bcursos: Yes there is. I sent you a friend request so we can discuss in chat.
bcursor Aug 24, 2017 @ 4:35pm 
Loved and donated thanks :) I cannot play without it.

Is this opensource, can I find the sourcecode? I want to improve it