duck-frost

Noun

duck's frost

1. A slight frost visible in the morning; (jocularly) rain (overnight).
   • The weather most unsuitable is that kind of frost which comes on in the early morning, and is accompanied with some rime on the grass—a duck's frost, just sufficient to check fox-hunting. Every footstep on grass in this condition when the sun comes out burns up as black as if the sole of the boot...1880, Richard Jefferies, The gamekeeper at home, sketches of natural history and rural life [signed R.J.]., page 146