This poem will be short, of course, maybe a quick observation, a moment preserved, as in this no-sentence poem by Ezra Pound:

In a Station of the Metro

The apparition of these faces in the crowd;
Petals on a wet, black bough.

Or maybe an apostrophe like H. D.'s "The Pool":

The Pool

Are you alive?
I touch you.
You quiver like a sea-fish.
I cover you with my net.
What are you—banded one?

Longer days. Shorter nights. A season of growth and renewal.

Here are are some poems offered for your for your summer reading by The Academy of American Poets.

"Vacation"  by Rita Dove
"In Summer"  by Paul Laurence Dunbar
"Spain"  by Major Jackson
"Long Island Sound"  by Emma Lazarus
"Travel"  by Edna St. Vincent Millay
"Back Yard"  by Carl Sandburg
"The Idea of Order at Key West"  by Wallace Stevens

Be sure to check the "Related Poems" links on each page.