Christmas Day is December 25th. In a non-leap year, there are 31 days in January, 28 in February, 31 in March, 30 in April, 31 in May, 30 in June, 31 in July, 31 in August, 30 in September, 31 in October, and 30 in November. Summing these (31+28+31+30+31+30+31+31+30+31+30) equals 334 days before December, plus 25 days in December equals 359.