Vernal equinox Vernal equinox Solstice of winter. Solar thermal conditions in the northern and southern hemispheres during the summer solstice.

On the vernal equinox, the sun shines directly on the equator, and the northern and southern hemispheres get as much light as heat.

From summer to the sun, the direct point of the sun reaches the northernmost point, the daytime in the northern hemisphere reaches the maximum value in a year, the northern hemisphere gets the most light and heat, and the daytime length and photothermal in the southern hemisphere are the minimum values.

Similarly, on the winter solstice, the direct point of the sun reaches the southernmost point of the direct range of the sun, and the southern hemisphere gets the most light and heat, and the day length also reaches the maximum. The length of day, light and heat in the northern hemisphere are the smallest.