The poem opens with imagery that illustrates the beauty and tranquility of nature. "There will come soft rains and the smell of the ground," the speaker says in line 1, setting forth a peaceful, soothing vision of the future. The sound of gently falling rain—along with the earthy smell that rises when this happens—creates a pleasant and calm atmosphere, allowing the speaker to emphasize the serene beauty of the natural world.
There is also an inherent sense of optimism in the phrase "there will come," which gestures toward the future. In this future, the speaker indicates, there will be little more than "soft rains" and the sight of swallows (a kind of bird) flying overhead. Using sound-related imagery, the speaker brings this atmosphere to life, noting the "shimmering sound" of the birds and, in doing so, hinting that there will be nothing to disrupt nature's bright, joyous music.
Of course, as the subtitle tells readers, this optimistic vision of the future sits against the backdrop of war. Given that the poem was published in 1918 (and reprinted in slightly different form in 1920), readers can gather that the specific war in question is World War I.
This idea of a peaceful, harmonious future therefore contrasts with the brutal realities of one of the most gruesome wars in human history—brutal realities that the speaker never directly acknowledges. The speaker prefers to focus on nature's grandeur, which the poem implies exists separately from humanity's destructive tendencies.
The speaker's use of sibilance in these opening lines helps lull readers into the poem's relaxed and peaceful environment:
There will come soft rains and the smell of the ground,
And swallows circling with their shimmering sound;
The hissing of the sibilant /s/ (as well as /z/ and /sh/) softens the speaker's language. In fact, many of the consonant sounds in these lines add to this pleasing effect, leading to a sense of euphony—the combination of the /m/, /l/, and /w/ sounds are particularly noticeable (in words like "smell," "swallows," and "shimmering"). The language thus reflects the same feeling of ease and wonder embodied by nature itself.