(a.) Cold as a stone.

Siberian aguey aguish arctic below zero biting bitter bitterly cold bleak blue with cold boreal brisk brumal chattering chilly cold cold as charity cold as death cold as ice cold as marble cool crisp cutting dithery freezing freezing cold frigid frozen frozen to death gelid glacial half-frozen hibernal hiemal hyperborean ice-cold ice-encrusted icelike icy inclement keen nipping nippy numbing penetrating piercing pinching raw rigorous severe shaky sharp shivering shivery sleety slushy snappy stone-cold subzero supercooled winterbound winterlike wintery wintry with chattering teeth