Which solar term has come, and the daylight time in the northern hemisphere is the shortest?

The winter solstice is the shortest day and the longest night in a year.

Because the earth rotates around its axis, but this axis is not perpendicular to the ecliptic plane, and the included angle is 90 degrees -23 degrees and 26 minutes, which determines that the sun cannot shine on the same latitude of the earth all the year round when the earth revolves. At the vernal equinox (3.2 1), the sun shines directly on the equator, with the same time of day and night, and at the summer solstice (6.22), the sun shines directly on the Tropic of Cancer. The Antarctic circle is extremely night, and the autumnal equinox is the same as the vernal equinox. In winter solstice (12.22), the sun shines directly on the tropic of Capricorn, and the days in the northern hemisphere are short and the nights are long. The polar night appears in the Arctic Circle, and the polar sunrise appears in the Antarctic Circle.