The Resident Skeptic turns seven today.
She: *waking up one morning this summer* Amma, it's so cold today!
Me: Yeah it rained all night.
She: How do you know?
Me: I woke up a couple of times during the night, and I heard the rain both times.
She: That doesn't prove anything. It could just have been raining when you woke up, and it could have stopped when you went back to sleep. The correct thing to say would be: "It rained for at least some time last night."
Absolutely right, kid. Don't ever stop questioning everything!