An ice thickness probe includes a longitudinally-extending probe rod, an insulator casing and a sleeve. The probe rod is fabricated from an electrically-conductive material. The insulator casing is fabricated from an electrically-insulative material and is wrapped around, is in contact with and extends along the probe rod. The sleeve is fabricated from a stiff yet resilient material and is wrapped around, is in contact with and extends along the insulator casing. The insulator casing and the sleeve are concentrically disposed about the probe rod as viewed in cross-section. An ice thickness probe assembly includes a frame structure, a reference bar and at least one ice thickness probe. An ice thickness monitoring apparatus is used in a thermal storage coil having a tank containing water and a tube disposed in the water so that, when the thermal ice storage coil is energized, ice is produced and accumulates on the tube.