At its release, Need For Speed World was only available in daytime. Changing daytime cycle was added in a patch during the Open Beta in June 28th, 2010, where as the Night mode was added in December 16th, 2010.
Early on, the cycle was 7 hours long, with day 3 hours, night 3 hours and sunrise/sunset about 30 minutes each. This was reduced to 5 hours 40 minutes. 4 cycles was 22 hours, 40 minutes, so each real day, the pattern started 1 hour and 20 minutes sooner. It took 72 cycles or 17 real days for the full pattern to repeat. Later, each day at GMT 0:00, the cycle was set back 1 hour and 20 minutes from day to dawn so that the cycle was the same on each day . Night time started at GMT 04:35, 10:15, 15:55, and 21:35. On New Years, there was 24 or 48 hours of night time.
The time of day usually stays the same for a player until they enter the safehouse and exit back out or go through a tunnel (some tunnels don't have this effect), but if the player doesn't do either of these things to reset the day, the game will automatically force the time to reset. The sun still moves gradually in one line above the horizon.
During the day, the sky is light blue with scattered clouds. In the evening, the sky is orange near the sun, while on the other side is dark greyish blue, also with a few scattered clouds. At nighttime, the sky is black. There are clouds, and the moon is hidden behind them. In the morning, there is one giant cloud covering half the sky, and the other a greyish blue, with the sun between the cloud and the open sky. Then the cycle starts over again.
At nighttime, all the buildings are illuminated, and car's headlights and taillights are on.