Why Does The Temperature Drop Sometimes Right After Sunrise?

Tools

By By Steve Pool

SEATTLE - One reader noticed that sometimes the temperature seemed to drop a couple of degrees right after sunrise.

On clear and calm nights, the ground radiates its absorbed heat back into the atmosphere, allowing temperatures to cool at night. But since cold air is heavier that warm air, the cold air will pool right near the ground.

In this case, in the moments before sunrise, it might be 40 degrees at your head but 36 degrees at your toes. When the sun comes up, the ground starts warming.

As that warm air rises, will begin to mix the colder air near the surface with the warmer air above -- thus making it warmer at your foot but cooler at your head (perhaps now it's 38 at both your head and your foot).

That would only happen on nights without much wind and generally clear skies. Otherwise, wind will keep that layer mixed up and cloudy skies don't allow much heat to radiate back.

Your Photos

YouNews Up! Up! And away! Up! Up! And away!
When I saw this dramatic cloud to the north, it reminded me of smoke, rising in billows until it hits the jet stream, then it's pulled hundreds of miles east. I had to capture it quickly. Within minutes the effect had faded.
YouNews Inside an osprey nest Inside an osprey nest
For my girlfriends birthday we had a party at her parents. We knew the nest was there but the owner hadn't seen or heard the osprey for a day or two. He asked me to fly my drone up and see if any was wrong. I flew up and found that there were two eggs inside.
YouNews Our Garden Our Garden
The growing season has been great.

The secret to this garden is simple.
I used recycled grass clippings.