The title borrows a famous line about vanished snows, and the poem plays with it in a small, wry way. The speaker sits in a barber's chair, watching cut hair fall, and rejects the idea that this is a wintry, melancholy moment where he is "snow" being swept away. The falling hair might be gray or white, but he refuses to turn it into a grand image of loss.
Instead, he calls the experience "a sack of hard time, late and gone." Time is something heavy and bundled up, and it's already over. What's striking is the last turn: afterward, he reads a clock "with pleasure." Time is no longer a threat, just something to check.
The mood is dry, calm, and quietly funny. The speaker seems to shrug off the old poetic habit of mourning for the past, and finds a lighter, almost relieved attitude toward aging, based on the poem's tone and wording.