The reason why the weather in northern Heilongjiang is cold and long

Heilongjiang is near the Tropic of Cancer in the northern hemisphere. In winter, the sun shines directly on the Tropic of Cancer in the southern hemisphere, so the northern hemisphere receives less sunlight, so the weather is cold and long.

When the direct sunlight returns from the tropic of Capricorn and gradually approaches the northern hemisphere, the weather will get warmer.

By the way, it's the winter solstice, and the direct sunlight has just passed the tropic of cancer. On the contrary, the Tropic of Cancer with direct sunlight is the summer solstice, which is the warmest time in the north.