(i) “Humid shadows” refer to the dark clouds that produce rain.
(ii) “Starry spheres” refer to the night sky abounding with stars.
(iii) "What a bliss" refers to the happiness of the poet. When it rains, the poet gets into his cottage and enjoys the patter of rain upon the roof.
(iv) This refers to the various imaginary thoughts and fantasies that are aroused in the poet’s mind.
(v) This phrase means that numerous memories intermingle to form a beautiful picture that the poet recollects.
