Examples:

• Getting him to admit he was wrong is like waiting for a cold day in July.
• She said she'd quit her favorite hobby when pigs fly or on a cold day in July.
• You'll see me wearing a suit to work on a cold day in July before you see that happen.
• I'll believe he's on time when I experience a cold day in July.
• He promised to apologize when it's a cold day in July, and I think that's about to happen.
• Trusting him with my secret is something I'll do on a cold day in July.
• You can expect him to apologize sincerely when it's a cold day in July.
• She said she'd quit eating chocolate when it's a cold day in July.
• You'll catch me willingly cleaning my room when it's a cold day in July.
• I'll believe that excuse when it's a cold day in July.
• I'll be ready for that challenge when it's a cold day in July.
• I'll agree with his opinion when it's a cold day in July.
• He'll admit he was wrong when it's a cold day in July.
• You'll find me jogging willingly when it's a cold day in July.
• I'll forget that embarrassing moment when it's a cold day in July.
• They'll start the project on time when it's a cold day in July.
• I'll start enjoying country music when it's a cold day in July.
• She'll admit defeat when it's a cold day in July.
• You'll find me at the gym regularly when it's a cold day in July.
• He'll stop making excuses when it's a cold day in July.