Sunrise/Sunset Season Offset (More Realistic Sun Times!) by Gurra
This mod is now primarily hosted at ModTheSims: http://www.modthesims.info/download.php?t=541811
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As a Swede, I always thought sunrise and sunset times in The Sims 3 were stupid. This lead me to create the Longer Days Mod three years ago (hosted at MTS: http://modthesims.info/download.php?t=421863) but when the Seasons EP released I felt there was more to be done... EA had made a sunset/sunrise offset that changed the times over the seasons but it just wasn't right. They still had day between 6 and 18 in summer and then shorter days all the other reasons which made no sense to me. So here's a mod changing the offsets, without changing the INI files. 
There are two versions of the mod, and you should only use ONE at a time:
Stockholm
This version changes the sunrise/sunset times to a more realistic one, matching the ones in Stockholm, Sweden - which happens to be my hometown. I used the Stockholm sunrise/sunset data from 2013 for spring equinox, summer solstice, autumn equinox and winter solstice and applied these to the four seasons. This makes for these sunrise/sunset times*:
Spring - 5:30/18:00
Summer - 3:30/22:00
Autumn - 6:30/19:00
Winter - 8:30/15:00
* These are the sunrise/sunset times if the game uses INI files specifying standard sunrise and sunset at 6 and 18, if these values are changed the game will offset from the modified values.
Polar
This version changes sunrise/sunset times to reflect midnight sun and polar night, having these sunrise/sunset times*:
Spring - 6:00/18:00
Summer - Sun never sets1
Autumn - 6:00/18:00
Winter - Sun never rises2
* These are the sunrise/sunset times if the game uses INI files specifying standard sunrise and sunset at 6 and 18, if these values are changed the game will offset from the modified values.
1 In-game this will work as such as the sun sets at midnight, then suddenly flips over to the other side of the world and rises the minute after.
2 In-game this will work as such as the sun rises at noon, then suddenly flips over to the other side of the world and sets the minute after.
Feel free to request your own versions and I might make them for you and upload here. There is also a guide on how to do it yourself, you can find it further down.
Requirements and Compatibility
This mod does not require the Seasons EP, but since all the changes are to Seasons related code it will do nothing useful if you don't have the EP.
This mod does not change any INI files and is therefore compatible with all lightning mods making changes to sky colours etc.
This mod makes changes to the SeasonsManager_0xda46c4abc19a24ff.xml file and is not compatible with any mod making changes to the same file.
This mod is made and tested with game version 1.57, and confirmed compatible for all patch versions up to and including 1.67, but should probably work with all patches down to the Seasons patch. I doubt they have made any changes to the XML since the EP release. Using it on a lower patch level is on your own risk though.
Download
- Stockholm version
- Polar version
How to modify Sunrise/Sunset Season Offset mod to have your own times
First of all you will need s3pe to do this, you can find the latest version here: http://www.simlogical.com/ContentUploadsRemote/uploads/189/
1. Make a copy of your Gurra_SunriseSunsetSeasonOffsets_z.package file - z will be the version you downloaded from me (Stockholm or Polar).
2. In s3pe go File/Open...
3. In the Open package box locate your copy of the mod file and open it.
4. Right click the XML file (there should be only one) and choose Notepad in the menu.
5. The XML file will open in Notepad and locate the code for sunrise/sunset offset times. You will be looking for this part:
<kSummerSunriseAndSunsetOffsets value="x, y">
<!--Summer Sunrise/Sunset hour time offsets.-->
</kSummerSunriseAndSunsetOffsets>
<kFallSunriseAndSunsetOffsets value="x, y">
<!--Fall Sunrise/Sunset hour time offsets.-->
</kFallSunriseAndSunsetOffsets>
<kWinterSunriseAndSunsetOffsets value="x, y">
<!--Winter Sunrise/Sunset hour time offsets.-->
</kWinterSunriseAndSunsetOffsets>
<kSpringSunriseAndSunsetOffsets value="x, y">
<!--Spring Sunrise/Sunset hour time offsets.-->
</kSpringSunriseAndSunsetOffsets>
x defines the offset from normal sunrise time, normally 6:00*, during that specific season. An offset of -2 means 2 hours earlier than normal time which is 4:00.
y defines the offset from normal sunset time, normally 18:00*, during that specific season. An offset of 3.5 means 3,5 hours later than normal time which is 21:30.
*The numbers in the XML files only define offset from the normal time, not exact sunrise/sunset time. Some worlds have their own defined normal time that doesn't correspond to the standard one. For example, store world Aurora Skies has its normal sunset time at 18:06 instead of 18:00.
6. Edit the numbers to fit your wanted sunrise/sunset times for all four seasons.
If you are looking to match them to a real world location you will have to find data for all the seasons - I recommend checking sunrise/sunset times for your location at summer solstice, autumn equinox, winter solstice and spring equinox.
Here is an example from my Stockholm version:
<kSummerSunriseAndSunsetOffsets value="-2.5, 4">
<!--Summer Sunrise/Sunset hour time offsets.-->
</kSummerSunriseAndSunsetOffsets>
<kFallSunriseAndSunsetOffsets value="0.5, 1">
<!--Fall Sunrise/Sunset hour time offsets.-->
</kFallSunriseAndSunsetOffsets>
<kWinterSunriseAndSunsetOffsets value="2.5, -3">
<!--Winter Sunrise/Sunset hour time offsets.-->
</kWinterSunriseAndSunsetOffsets>
<kSpringSunriseAndSunsetOffsets value="-0.5, 0">
<!--Spring Sunrise/Sunset hour time offsets.-->
</kSpringSunriseAndSunsetOffsets>
7. Save the file and close Notepad. s3pe will ask you if you want to commit changes, click Yes.
8. Go File/Save and save the .package file.
9. Put your new, modified package in your Mods folder. Remember to never have more than one version of the mod in your Mods folder at the same time.
Disclaimer: If you upload your modified version, please give me credit and link to both this guide and the download thread for my mod. Thank you.