Wiktionary
raining buckets
vb. (present participle of rain buckets English)
Usage examples of "raining buckets".
It was raining buckets by then, the trail disappearing back into the earth as quickly as it was made, and Coil was too weak to give chase in any case.
When they reached the outskirts of Pensacola, it was raining buckets.
That jungle looked pretty mean, and on top of that it looted like it was raining buckets over there.