Why isn't the winter solstice on the same day each year?
为什么每年的冬至都不是同一天？
The date of the winter solstice varies from year to year for people in different time zones. It typically occurs around Dec. 21 or 22, though on rare occasions it can be as early as Dec. 20 or as late as Dec. 23, according to the Weather Channel.
根据天气频道的数据，对不同时区的人们来说，冬至的日期每年会有变化。多数年份的冬至日都在12月21日或者22日，偶尔提早到20日，或者错后到23日。
That's because our calendars aren't a precise match to the solar year.
这是因为日历与阳历并非完全吻合。
Schneider writes: "Earth takes about 365 1/4 days to orbit the Sun. Next year, the moment of the solstice will be about 6 hours later at 5:23 pm ET. In 2019, it will be at 11:19 pm ET, so for people living in Puerto Rico and other time zones to the east, the date of the solstice will be on the 22nd."
施奈德写道：“地球围绕太阳公转周期为365又1/4天。明年的冬至比今年大约迟6个小时（美国东部时间下午5点23分），后年又推后到美国东部时间晚上11点19分。所以对于居住在波多黎各及以东时区的人们来说，冬至日期是22日。”
为什么每年的冬至都不是同一天？
The date of the winter solstice varies from year to year for people in different time zones. It typically occurs around Dec. 21 or 22, though on rare occasions it can be as early as Dec. 20 or as late as Dec. 23, according to the Weather Channel.
根据天气频道的数据，对不同时区的人们来说，冬至的日期每年会有变化。多数年份的冬至日都在12月21日或者22日，偶尔提早到20日，或者错后到23日。
That's because our calendars aren't a precise match to the solar year.
这是因为日历与阳历并非完全吻合。
Schneider writes: "Earth takes about 365 1/4 days to orbit the Sun. Next year, the moment of the solstice will be about 6 hours later at 5:23 pm ET. In 2019, it will be at 11:19 pm ET, so for people living in Puerto Rico and other time zones to the east, the date of the solstice will be on the 22nd."
施奈德写道：“地球围绕太阳公转周期为365又1/4天。明年的冬至比今年大约迟6个小时（美国东部时间下午5点23分），后年又推后到美国东部时间晚上11点19分。所以对于居住在波多黎各及以东时区的人们来说，冬至日期是22日。”
