Nisha says the hottest part of the day is 12 noon, because that is when the Sun is highest

Why

Nisha's reasoning has a real fact in it — the Sun's rays ARE strongest around noon, when it is highest. But the air does not heat up directly from sunlight; it heats up from the GROUND, which soaks up the Sun's energy and then warms the air above it. And the ground keeps absorbing more heat than it loses for a couple of hours after noon, so the ground — and the air above it — carry on getting hotter well past midday. The temperature peaks only when the ground finally starts losing heat faster than it gains it, which is usually around 3 in the afternoon. Test it: notice when a summer day actually feels most unbearable — it is mid-afternoon, not the moment the Sun is overhead. Her brother is right: the hottest part of the day comes a few hours after noon, because the ground keeps storing heat and passing it to the air after the Sun's peak.