(a bit) black over Bill's mother's

(a bit) black over Bill's mother's

Said when the sky is dark and cloudy, and it is likely to rain. Primarily heard in UK. You better get that stuff off the lawn—it's looking a bit black over Bill's mother's. It's black over Bill's mother's so bring an umbrella with you. The raincoat is overkill now, but it was black over Bill's mother's when I left the house this morning!
See also: black, over
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
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