I use my computer at night, but my computer screen looks like daylight and I find it too bright to use at night.
So, what is a good tool to make my computer screen warmer at night? I'm using Windows 7.
A tool that you can use for this purpose is f.lux. Just enter your location, and the lightning that you have. Then, at night (the time between sunset and sunrise), f.lux will give your screen warmer colours, and during day (between sunrise and sunset), f.lux will make your screen look like daylight.
It works good and is cross platform, but the disadvantage is that it could be that you, even after sunset, don't yet feel the need of making your screen warmer. So you shouldn't think that with f.lux, you will never have to adjust the brightness of your screen manually.
redshift was designed to do that, in the background, and even doing a transition while the sun is not yet fully gone:
redshift – Adjusts the color temperature of your screen
The color temperature is set according to the position of the sun. A different color temperature is set during night and daytime. During twilight and early morning, the color temperature transitions smoothly from night to daytime temperature to allow your eyes to slowly adapt.
This is now a built-in feature in Windows 10 called Night light. You can enable it by following the instructions in this article on Microsoft Support.
This is an old question and you mention that you are using Windows 7. If this is still the case, I would recommend upgrading to Windows 10 by following the steps in this article on The Verge. Apart from giving you a native solution for twilight mode, updating to Windows 10 will come with significant security improvements to your machine.