Open your eyes

[Mostly Holy]

Okay let me have another go. I think this version is much better!

Method: Your rhymes are clean, which is appropriate for a sonnet but less so for your subject matter, which is pretty dark. I think a few slant rhymes might help, especially in the later seasons. You could rhyme "wind" directly with "end" in your winter stanza, for example. Some good euphony but it is not consistent, consider varying the consonants and internal rhymes between seasons, making summer mellow and winter sharp and hard acoustically.

Manner: The strict form you are using demands that you do not waste a single syllable on anything trite, cliche, or just filler. Sixteen syllables is not much to pack in a season and a stage of life so you have to make every word count double. To this end I have highlighted every part of your poem that I think you could use more vivid and original imagery in, or where I thought the imagery was muddled or unclear. I am not suggesting you change every one of them, or any of them, just that these are the ones that jumped out to me. Cliches are in green, confusing images in pink, weak phrases in blue: 

A verdant terrain.                           
Nature’s gift, a fertile ground.      
Drenched in April's rain.               

Yet burning waves bound.             seems more like an autumnal image
Over land, and sunlight spreads.
Under mid-life’s crown.

Crescent yellow threads.                 confusing image, is it a field of wheat? Why it is a crescent?
Ancient branches crack and bend.    
Now weeping soft reds.                  melodramatic and unclear

Sharp freezing winds rend.
Extinguishing warmth within.          winter is already cold, unless you mean warmth within houses, which seems thematically unrelated?
Exit Old Year's end. 

Melting snow signals the next cycle's spin.        
Everything will change, but your kith and kin.     

Matter: You are erring very much on the side of "nature poem", your metaphor is somewhat lost. I think more images that could be either nature or human, like "withered limbs" and "fraying tops" could help push the parallel development of the seasons and the stages of life. Your closer needs much more of a bite, the one you have is rather sentimental and also confusing. "death changes everything, except our friends and family" does not follow form your poem, and is obviously factually untrue as well. I also think it is a mistake to mention April, or the years end, directly. Haikus work best when they play it coy and force the reader to interpret images hidden in tight wordplay.

In all I really liked this version, I think your edits really helped and I look forward to seeing the next version, if you make one.