Starting the poem with sunshine makes it a brilliant start as related to the title (the summer).
The 2nd line I think can read better if you just say "hiding" instead of "which is hidden" after ending the 1st line with a comma.
The first three stanzas follow the same style of arrangement in the components of each sentence.
This feature makes the reader love the poem.
Also stanzas 4,5 & 6 follow another same but normal style in each.
I think the tense should be edited in the following phrase:
"Fresh green grass no longer growing"
Either you change "growing" to "grows" or you add "is" after the word "grass".

stanzas 7 & 8 are sorrowful but we know that nobody can refuse what the nature bears for the future.

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Overall:
I recommend and guarantee that the great metaphor and similes used in the poem make it of top quality. You always lighten the readers thoughts with such amazing poems. Thank you for sharing it with us.

I always love the use of flowers in poems. Actually nature in general. The way you use your metaphors in poems are some of the best I have ever seen indeed. I love how you use winter as darkness and all the decribing words for it. Everything here seems to die and the people hide which is great for the tone of the poem you wrote here. The title works very well here. When summer dies life seems to halt and not as many things are alive. Like I said people isolate and sadness comes. The imagery here is immaculate. As I said the imagery plays out so well in my head and its sad how true this is here. The first two lines are my favorite because it is so simple yet it says so many things. They also have a deeper meaning behind them. The sun is light and light is happiness and when the joy goes away people do to. The tone is sad with so much deeper meaning! 5/5