The normal Second Life "day" cycle is only four hours long. There are three hours of daylight, and one hour of night. There are some good reasons for this. For one thing, most of us can't spend a whole 24 hours, or even 12 hours in world at a time. The short day cycle gives most people a chance to experience a "day", or at least a major portion of a "day." The imbalance between the amount of daylight and the amount of night is helpful for most people. It makes it easy for builders...there's more time when they can see what they're doing. Plus, arguably, more things are done during the hours of daylight than during the hours of darkness. Also, Second Life has a worldwide audience. Having six "days" in each 24 hour period ensures that no matter what time zone you live in, or when you're able to log into SL, you can experience a "day" in Second Life.
But if the time of day doesn't happen to match your mood, or the activity that you had in mind, you don't have to wait a couple of hours for your desired time of day to roll around. You can tailor your personal Second Life experience to show you any time of day, and a lot more besides. That's the job of the Environment Editor.
For most purposes, the "quick settings" found under the World Menu ---> Sun Position are perfectly adequate. There are four "times of day" and you can select any one of them with the menu or with the setting's keyboard shortcut. Selecting one of these sets your viewer to the appropriate sun position, and overrides any customized region sky and water settings, using the SL defaults for those.
Sunrise -- CTRL+SHIFT+U
Midday -- CTRL+SHIFT+Y
Sunset -- CTRL+SHIFT+N
Midnight -- CTRL+SHIFT+X
These quick settings are not persistent...they will be canceled if you teleport to a new region, or the next time you log in.
You can do a lot more than that to customize your view, though. Have a look at the World ---> Environment Editor controls, just below the Sun Position quick settings. Here, you can customize the look of the sky that you see...sun position, haze, amount and speed of clouds, sky color and many other settings. You can customize the look of the water, too...its transparency, waviness, and color. There are a ton of ready-made "presets" for both sky and water, and you can also make and save your own. Creating a dramatic sky and water look is something that a lot of Second Life photographers really enjoy doing. You can also make a custom day cycle, using up to twenty different sky presets that either you or others have made.
Here's a little gallery to show you the range of possibilities. All the shots are of my home region of Masocado, taken at the same position. The first four show the default settings at the four "sun position" quick settings, and the last four show various Windlight sky and water settings.
|Windlight sky and water presets...|
Any changes you make to your sky and water and day cycle settings are only seen by YOU. This is why you hear things like, "Oh, set midnight! It looks so romantic." But there are a couple of exceptions to this.
If you are the owner or estate manager of an entire region in Second Life, you have the ability to apply sky and water presets, and even a custom day cycle to the entire region. Of course, your visitors can override this in their own viewers, but it's a nice touch to set the exact "look" you want your visitors to experience. Owners of vampire and dark urban roleplay regions, in particular, appreciate the ability to create a land where it's always midnight.
If you use the popular Firestorm third party viewer, it has an option called "Parcel Windlight." This allows you to set the sky and water settings of any land parcel you own, just as an estate manager would do with a region. However, people who don't use the Firestorm viewer, or who DO use it but have not enabled the Parcel Windlight feature, won't see your custom settings. Here's a link to an article explaining how to use Parcel Windlight in Firestorm: Firestorm Sky and Water
By the way, the term "WIndlight" comes from way back in SL history. The improved sky and water look, when it was under development, was called "Windlight." When it was implemented in the viewer, the term stayed on, to distinguish the new functions from the older, "classic" sky and water. The classic options hung around for a long time, because they were easier on graphics resources. In fact, they're still there, except for the "classic clouds," in the Preferences setting "Basic Shaders."
The classic clouds were actual volumetric clouds, which existed in the atmosphere at about 100m altitude. This created a problem for some builders of tall buildings and low skyboxes...but I sort of miss them. Today's Windlight clouds are prettier, but they are painted on the sky an infinite distance away, and you cannot pass through them or get above them.
Have fun experimenting with different Environment settings! Especially if everything has begun to seem ordinary and everyday -- a different environment can give even familiar sights a whole new look.
Here are some links to a lot of user-created Sky and Water presets!
Second Life Wiki
Blogger's List of Presets
Penny Patton's Day Cycles and Skies