Three short lines say almost everything there is to say: someone is going home, and the reason is rain. There is no complaint, no drama, no dwelling on what was interrupted. The speaker simply reports a small change of plan, the way you might jot it in a notebook or text it to a friend.
What makes the poem interesting is how much it leaves open. We don't know where the speaker was headed, or whether they mind turning back. The flat, matter-of-fact tone suggests acceptance rather than annoyance, as if the rain has made the decision and there's nothing to argue with. The line break after "due to" even makes the sentence pause for a moment before the rain arrives, a bit like a few drops before the downpour.
The mood is quiet, calm, and a little wistful. It captures that ordinary feeling of giving way to the weather and heading for shelter.