When did spring begin?

1February 4th, 999 is beginning of spring.

According to Baidu calendar,1February 4, 999, the 19th of the twelfth lunar month, beginning of spring, Wuyin Year, Bingyin Month, Dinghai Day is a tiger, Thursday, the 6th week.

Beginning of spring is the first of the 24 solar terms. Standing means "start"; Spring represents warmth and growth. Twenty-four solar terms were originally formulated on the basis of "variable stars". When the bucket handle of the Big Dipper points to the shade, it is beginning of spring. At present, solar terms are determined according to the longitude of the sun. When the sun reaches longitude 3 15, it will be the beginning of spring, and the festival will be held from February 3 to 5 of the Gregorian calendar every year.