Why the coldest part of a night is most of the time at dawn? How do we explain this signifiant temperature drop?
EDIT: I get answers telling that’s because sun has been out the longest when sun rises again. Indeed it makes sense that the night will continuously go coolest, but the weird thing is: There is a real, proper drop on the thermometer every morning at the dawn, event if we stayed at 5°c all night long, at the very first lights, it will drop to 4°c and then go back to 5°c a moment later (actually happened again this morning).
The reason of this radical drop is my question.
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In: Geology
The entire night the earth, which held a lot of leftover heat (like how a baked potato stays hot once its out of the oven, is releasing its heat. At sunrise, the maximum amount of heat has been released before new heat is introduced by the sun. And while it seems like the sun should make things warmer at sunrise, the sun is not actually above the horizon at sunrise. It’s really like 6 degrees or so below the horizon and we can see it because the atmosphere bends the light towards our eyes. There is also some debate about evaporative cooling from the dew, similar to how sweating makes us cooler, but I believe this is largely trivial.
I figure that the world is like a rock that was out in the sun. The sun goes away and it starts cooling down and getting cooler and cooler at a steady rate.
Until the sun comes back and starts warming it up again.
So it’s always coolest when it has been out of the sun the longest. Which is right before dawn.
The temperature drops at a steady pace while the sun is down, just before dawn is coldest because the sun has been down the longest.
It often feels colder, because psychologically we expect it to be warmer when it is light out, and the same temperature will seem colder as the sky lightens.
> There is a real, proper drop on the thermometer every morning at the dawn,
This seems so unlikely that you’ll need to provide some evidence. [Here are the numbers](http://www.bom.gov.au/products/IDN60903/IDN60903.94926.shtml) where I live and there’s no sign of weird dips just before dawn (7:20am currently) over the last few days. Can you find something similar where you are?
> event if we stayed at 5°c all night long, at the very first lights, it will drop to 4°c and then go back to 5°c a moment later (actually happened again this morning).
On this occasion I’d guess that it went from 4.5°C down to 4.4°C and then back up again. Those numbers round to 5°C and 4°C which makes it seem more dramatic.
My understanding has always been that once the sun rises just a little, that energy causes the cold air to move, thus feels colder.
Does that sound plausible?
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