Sleet
Half-frozen rain — weather that is neither one thing nor the other and unpleasant in the way only that combination can be.
Sleet in a dream is the dream's image of weather that refuses to be one thing or the other. Sleet is not snow and not rain; it is the wet, half-frozen compromise that does not look beautiful and does not wash the air clean. The dream brings sleet when something in your life — a season, a mood, a phase of a relationship — is currently in the unpleasant in-between, neither the warm version nor the cold version, and is making everything outside it slightly miserable. Sleet endured under a good coat is the dream affirming that the unlovely middle is survivable. Sleet that has gone on for days, the ground neither freezing nor draining, is the dream noting that the in-between has overstayed, and the cost of it is now more than either of the two cleaner weathers would have charged.