I don't find îngheț in Wiktionary as a translation of 'frost'; it says that is brumă. Is brumă more frequent than îngheț?
They do not have the same meaning in Romanian. Let me try to shed some light on the meanings of ger, îngheţ and brumă:
ger = frost (cold weather)
îngheţ = 1. (the act of) freezing; 2. (by extension) frost (cold weather)
brumă = hoarfrost, frost (cover of minute ice crystals)