Hello and welcome to the read me of GTA real time mod, a small modification which syncs your in-game time to your current system's time to allow you, the player, to experience the time playing the game in the same way us humans tend to do in real life.

Before going forward with anything else I want to tell you this is NOT my own mod, I haven't got anything to do with creating it. This is merely an attempt at getting this mod into the spotlight more and while I am at it, write a more comprehensive set of instructions. All credit for the creation goes to the original creator, "The Hero".
This is where I found a link to this mod orginally https://gtaforums.com/topic/869175-real-time-clock/
I am a aware that the Nexus page descriptions already link to this but there is no harm being redundent in this case I think. Note that gtaforums's links (at least in the thread linked) do not work on my end and only bring up the page I was already on.
Download links, some additional notes and a small table for your convenience to keep track of the in-game time are included below. Thanks for using "The Hero"'s mod and thank you for reading this introduction.

Original read me by "The Hero":

"Keeps game clock in sync with system time.
Works with III/VC/SA 1.0"

How to install.

1. Use an downgrader to get the 1.0 version for whichever game you want to play. Download links below, just copy and paste them in your internet browser of choice.
2. Follow the instructions of the downgrader
3. Insert the map called "src" (without quotation marks) in the GTA directory. If you cannot find it, just search for your GTA game on your operating systems. Guides for this can be found online if you are still stuck. Following the previous insertion, also add "realtime" (again, without quotation marks) in either "scripts" in the GTA diretory or where you have inserted "src"

Downgrader download links:

(Note that I cannot 100% vouch for the contents of these downloads, do this at your own discretion)

General downgraders: http://downgraders.rockstarvision.com/

Alternative downgraders

GTA Vice City : Steam version https://drive.google.com/file/d/104wJUrQIrGfXm9L_JJaP72XftLhlF76S/view

GTA San Andreas : Steam version https://www.nexusmods.com/gtasanandreas/mods/2659
Rockstar version https://www.nexusmods.com/gtasanandreas/mods/2658

GTA III : Steam version https://apg-clan.org/vbdownloads.php?do=download&downloadid=1184

I wasn't able to find Rockstar downgraders with a quick search but perhaps you will. It might not even be needed, but I cannot speak with authority on this.


Additional notes:

* Saving the game no longer advances the in-game clock by 6 hours, this needs to be done manually (so changing your system's time) if so desired.
* This mod also functions for GTA LCS for PC, a port for that game running on a modified version of GTA: Vice City, this mod doesn't seem to work for a similar mod making GTA Vice City Stories playable for PC, however.

GTA starting times

GTA Vice City : 21:18
GTA San Andreas : 6:46*
GTA III : 4:09**

*Technically it might start a bit sooner as CJ walks down the alleyway, but the clock hasn't appeared yet)

**This time is a is a bit hard to get right as the camera needs to settle in from going to cutscene to the actual gameplay, I just went with time being displayed at the moment you can see the clock)

Time before pausing or quiting the game

GTA Vice City :
GTA San Andreas :
GTA III :