it's tipping down

be tipping (it) down

To be raining very heavily. Primarily heard in UK. We have a football match scheduled for tomorrow, but if it keeps tipping down like it is today, I'm sure that it will be cancelled. Looks like it's tipping it down outside again. I guess I won't be cycling to work this morning.
See also: down, tip

it’s ˈtipping (it) down

(British English, informal) it is raining heavily: There’s no way I’m playing football in this weather — it’s tipping it down.
See also: down, tip