A month's weather in Binzhou

When the sun directly hits the tropic of Capricorn, it is the winter solstice in the northern hemisphere, and the date is around 65438+February 22. The length of day and night in the northern hemisphere is as follows: the shortest day and the longest night;

When the sun shines directly at the equator, it is the vernal equinox in the northern hemisphere, and the time is around March 2 1. At this time, the length of day and night in the northern hemisphere is equally divided.

March 14 lies between the winter solstice and the vernal equinox, so the length of day and night in Binzhou varies.

Therefore, choose: B.