In "All Summer in a Day," Bradbury develops a dreary tone through imagery, word choice, and conflict.
One of the primary images in the story, of course, is the endless rain. It has been raining for "thousands and thousands of days," and every single gray day melts into the next. Margot, the only child who can accurately remember the sun, stands apart from the group. She is described as a frail shadow of the child she used to be:
[She] looked as if she had been lost in the rain for years and the rain had washed out the blue from her eyes and the red from her mouth and the yellow from her hair. She was an old photograph dusted from an album, whitened away, and if she spoke at all her voice would be a ghost.
The children hate Margot for her memories and for the possibility she has of returning to Earth and a constant sun. Margot misses the brief appearance of the sun due to their cruelty. After the other children frolic in its warmth, they return to their school with "their hands at their sides, their smiles
vanishing away." All of these images create a mood of a dismal existence.
Bradbury also chooses specific verbs that contribute to this same mood. Consider the following sentences:
A thousand forests had been crushed under the rain and grown up a thousand times to be crushed again.
And once, a month ago, she had refused to shower in the school shower rooms, had clutched her hands to her ears and over her head, screaming the water mustn’t touch her head.
They surged about her...
(All bold added for emphasis.)
The repetition of these strong and negative verbs increases the sense of desolation.
The primary conflict occurs between Margot, the only child who remembers the sun, and the rest of the children. They hate her for her knowledge of a warmth and light that they have never known. The sun here can be seen as a metaphor for goodness and insight; they have never experienced these influences, and they therefore hate that which they do not know. Eventually, the children understand that Margot spoke the truth, but they have hidden her away and stolen the experience from her. Thus, even the resolution itself is somber and forlorn. Margot is robbed of the experience that she desperately longs for.