It's pouring with rain!
'Dirotto' — di-ROT-to. Stress on the second syllable. Double 't'. The 'r' is rolled.
Use during heavy, heavy rainfall — more intense than regular rain. Particularly vivid expression that perfectly captures Italian weather-related drama.
'Piovere a dirotto' is an idiomatic phrase meaning to rain heavily or in torrents. 'Dirotto' comes from 'dirotto' meaning unchecked or unrestrained. It's more expressive than 'piove forte' (it's raining hard).
Sta piovendo tantissimo.
It's raining a huge amount.
Simple intensified version — clear and descriptive
Ci sta un diluvio!
There's a flood out there!
'Diluvio' (deluge/flood) — biblical intensity. Very Italian dramatic expression.
È un acquazzone tremendo.
It's a tremendous downpour.
'Acquazzone' = sudden heavy shower — evocative Italian word for a cloudburst
Mediterranean storms can be sudden and intense — what starts as a clear sky can become a torrential downpour within minutes, especially in coastal areas and during autumn. Being caught without an umbrella is a common Italian experience.