The weather's taken a turn for the worse.

Meaning

The weather has suddenly become significantly less pleasant.

Examples

• John: 'It was sunny just an hour ago, now it's pouring rain.'
• Alice: '<b>The weather's taken a turn for the worse.</b> I hope it clears up soon.'
• John: '<b>The weather's taken a turn for the worse.</b> Looks like we'll have to reschedule.'
• Alice: 'We were going to have a picnic, but look at those dark clouds.'