f.lux

1. Open Cydia

2. Search for f.lux
3. Tap Install

4. Adjust f.lux preferences using Settings | f.lux
5. If necessary wait for sunset

NOTE:
Known bug: on older devices with non-Retina displays, the transition from daylight to f.lux-light causes the screen to temporarily flicker. To prevent this bug, turn off the long-transition mode in f.lux preferences.

To adjust the f.lux preferences, open your device's Settings app, and click f.lux.

INFO:
f.lux fixes this: it makes the color of your computer's [ or iphone ] display adapt to the time of day, warm at night and like sunlight during the day.

It's even possible that you're staying up too late because of your computer [ or iphone ]. You could use f.lux because it makes you sleep better, or you could just use it just because it makes your computer [ or iphone ] look better.


Free for Windows.
(also available for Mac, Linux , and iPhone/iPad)

f.lux makes your computer [ or iphone ] screen look like the room you're in, all the time. When the sun sets, it makes your computer [ or iphone ] look like your indoor lights. In the morning, it makes things look like sunlight again.

Tell f.lux what kind of lighting you have, and where you live. Then forget about it. f.lux will do the rest, automatically.