What does it mean to be half lovesick and half cool, half misty and half sunny?

The meaning of these two poems is that half of the summer sky is sunny and the other half is foggy and rainy. Two lovesick people miss each other in this cool environment.

Generally, there is no need to emphasize the understanding of the original meaning of the poem too much, as long as you can appreciate the yearning and indifferent artistic conception contained in the sentence.