Big old fat rain vs Downpour

When to use each in English, with meaning, register, and examples.

Big old fat rain

InformalBeyond 10,000 (less common)

Downpour

Top 5,000 (fairly common)
Most formal: DownpourMost common: Downpour
 Big old fat rainDownpour
Pronunciation🇬🇧 //bɪɡ oʊld fæt reɪn//🇺🇸 //bɪɡ oʊld fæt reɪn//🇬🇧 //ˈdaʊn.pɔː//🇺🇸 //ˈdaʊn.pɔr//
MeaningA lot of heavy rain.A lot of rain that falls quickly.
ExampleWe had big old fat rain yesterday, and the streets flooded quickly.The forecast predicts a downpour this afternoon.
RegisterInformalNeutral
How commonBeyond 10,000 (less common)Top 5,000 (fairly common)
Collocationsbig old fat rain, heavy rain, falling rain, unexpected rain, pouring rainheavy downpour, unexpected downpour, torrential downpour, summer downpour
Common mistakesUsing in formal contexts where it's inappropriate., Confusing with other expressions for rain., Not understanding it's a colloquial phrase.Confusing downpour with drizzle, Using downpour in a non-weather context, Mispronouncing the word
Usage notesUsed in casual conversations, often to emphasize the heaviness of rain. Not commonly used in formal writing.Used in everyday conversations about weather. Not typically used in formal writing.

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Big old fat rain

Frequently asked questions: Big old fat rain vs Downpour

What's the difference between Big old fat rain and Downpour?

Big old fat rain: A lot of heavy rain. Downpour: A lot of rain that falls quickly.

Which is more formal: Big old fat rain and Downpour?

Downpour is the most formal of these.

Which is more common: Big old fat rain and Downpour?

Downpour is the most common in everyday English.

Can you show an example of each?

Big old fat rain: We had big old fat rain yesterday, and the streets flooded quickly. Downpour: The forecast predicts a downpour this afternoon.

Can I use Big old fat rain and Downpour interchangeably?

Not always. Big old fat rain and Downpour are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.