Chinese calendar follows lunar months. Various events and festivals are according to lunar months. A lunar month begins on the New Moon day, then 2nd day, 3rd day, ... up to 15th day (Full Moon Day), 16th day, ..., until 29th or 30th day. In Chinese tradition, New Moon days and Full Moon days are meant for worship in temple, ancestral rememberance, village/town market attendance.
The Chinese calendar gives one month or so to allow new year preparation and to welcome the spring. Occassionally, when a new moon fall on 21st/22nd December, the concept below is more accurate.
February 4th of the solar system is the day when the sun arrives mid-way in between the Equator and the Tropic of Capricon while travelling away from the Tropic of Capricon towards the Equator. This is the day when "Signs of Spring" show up, e.g. day light becomes longer, daffodil buds ready to blossom, peach buds ready to blossom, etc., though obviously still rather cold.
Winter Solstice: 22/12/01
1st new moon after winter solstice is 13/01/02
2nd new moon after winter solstice is 12/02/02 (Lunar New Year Day)
Shortest day: 21/12/00
1st new moon after 21/12/00 is 26/12/00
2nd new moon after 21/12/00 is 24/01/01 (Lunar New Year Day)
The New Moon Day before 04/02 is 06/01/00
The New Moon Day after 04/02 is 05/02/00
Lunar New Year Day is therefore 05/02/00
The New Moon Day before 04/02 is 17/01/99
The New Moon Day after 04/02 is 16/02/99
Lunar New Year Day is therefore 16/02/99
The New Moon Day before 04/02 is 28/01/98
The New Moon Day after 04/02 is 26/02/98
Lunar New Year Day is therefore 28/01/98