While it may be strange, Chinese New Year never occurs on the same day. Unlike the Gregorian Calendar of western civilisation, the chinese use the Lunar Calendar which has been used since 2697BC or 2637BC depending on who you speak to.
Chinese time is broken into days, lunar months, lunar years, and cycles of both 12 and 60 years. At the moment we're in the 79th 60 year cycle, the second 12 year cycle about to begin the year of the sheep or goat (depending on who you ask).
To keep the lunar calendar in line with the solar calendar the Chinese actually add a leap month every 30 to 34 months. This month is considered to be highly unlucky but is neccessary to keep the seaons in line with the months. Incindentally, this leap year causes the Chinese New Year to stay within the months of January and February.
Chinese New Year is not a random occurance though. It always happens on the second new moon after the Winter Solstice, the "shortest" day of the year and December 22nd on our calendar.
The other thing about Chinese New Year is that the festivites last fifteen days instead of the usual one in our culture. Each of the fifteen days holds a special significance. While too long for this article, you can find out about each day's significance here.
Even if you are a westerner, Chinese New Year makes a wonderful holiday and gives a chance for us to understand a different culture and their traditions. If you get a chance, I encourage you to go visit chinese communities and engage in the festivities.
Have fun and Kung Hei Fat Choi to you all!