The title sets the scene: someone drinking alone in the sun. The poem's first stanza turns to the things around the speaker, water and sun, and calls them "friends of drink." That's a quietly sad detail. When no people are there, the elements have to stand in as company. The speaker then asks them to "promise me a change," which sounds half like a wish and half like a plea. Something in this solitary moment isn't working, and the speaker hopes it will shift.
The second stanza says it plainly: "I miss joy / and idle talk / in the garden." The longing is for simple things, relaxed conversation and the lightness that comes with it. The mood is wistful and a little lonely, but gentle rather than despairing. Short lines and plain words leave a lot of space around them, so the loneliness feels quiet and real. The speaker doesn't complain loudly. They just name what is missing.