mobow

Well golly if that dont' make sense. I've wondered why that is, but it certainly does get colder a half hour before sunrise. Brrrrrrrrr

JoeRE

Dont really understand the logic there....but it feels 'colder' right after sunrise because our metabolism (what keeps us warm) is at its lowest of the day (for the vast majority of us). You probably did not eat breakfast, or if you did it was a very light one. You just performed some exercise getting to, and climbing into, the stand....now you body has nothing else for fuel and it starts to run slower (because now it is conserving what energy is remaining for your body to use....so, it feels 'colder'. Once the sun is up, it usually does get warmer ...and our bodies are 'waking up' so to speak(metabolism naturally speeding up as it would every day)....so the improvement is twofold.

I am pretty sure temperatures are at their lowest just before sunrise, not just after, on most days....but once again, it is about perception[8D].

jeremy3303

Its not so much that the sun is FORCING cold air to the ground, its more of the sun's gravity pulling up on the atmosphere and cold air moves in to replace the warmer air that was lifted away from the ground.

125py

yeah i have noticed that also

valor10

Yes, scientific fact it is coldest just prior to sunrise. It's actually quite simple. The ground is radiating heat back into the atmosphere all night. Just prior to sunrise is obviously the very end of this process, and hence the colder temps. Cloud cover keeps the night/morning warmer due to slowing the radiating of heat into the atmosphere.

JoeRE

That makes sense anyway.

BigJ71

Jeff,

What you're feeling is the diminishing effects of surface radiation. Through the night the effects of surface or "solar radiation" start to drop. As surface objects loose their radiant heat (from the sun during the day) it starts to cool. Somewhere during the early morning period, the radiation balance curve crosses thezero line (a balancebetween gain and loss) and therefore no temperature change.

The time of switching back to solar heatingbegins an hour or so just after sunrise because theincoming solar energy does not yet have enough strength to reverse the heat loss from terrestrial radiation.As a result, the surface and lower atmosphere air are still losing heat for about an hour after sunrise and thus the coldest temperature of the day has yet to be reached. This meansthe time of coldest temperatures areabout an hour after sunrise.

This of course does not take into effect weather fronts, I'm talking about a nice calm day and night with no major weather fronts moving through the area.

It's not in your head Jeff....