Why does the poem a spring morning begin with description of rain?

You're likely referring to the poem "Spring Morning" by William Blake. While the poem doesn't explicitly begin with a description of rain, it does begin with a description of the world after rain, which is a crucial element in setting the mood and theme of the poem.

Here's why the poem starts with a description of the world after rain:

* Renewal and Rebirth: The poem opens with "The Sun-flower turns on his stalk," suggesting a fresh start and a sense of renewal. Rain, as a cleansing force, symbolizes rebirth and the awakening of nature after a period of dormancy.

* Cleanliness and Purity: Blake uses imagery of a "bright clear sky" and "grass so green" to emphasize the cleanliness and purity that rain brings. This sets the stage for the poem's themes of innocence and spiritual awakening.

* Contrast and Transformation: The description of the world after rain contrasts with the potential darkness or despair that might have existed before. This juxtaposition highlights the transformative power of nature and the arrival of spring.

* Emotional Impact: The imagery of the "soft gentle air" and the "sweet smell" of the flowers evokes a sense of tranquility and peace. This sets a calm and contemplative tone for the poem.

The poem's opening lines paint a picture of a world reborn after rain, paving the way for the exploration of themes like innocence, joy, and the spiritual awakening that comes with springtime.