What's the science behind cold overnight temperatures?

Cold overnight low temperatures are enhanced with clear skies and light winds. Cloud cover and strong winds can lead to warmer overnight low temperatures.

Posted: Nov 9, 2020 5:51 PM
Updated: Nov 9, 2020 6:00 PM

CHICO, Calif. - Cold overnight low temperatures are enhanced with clear skies and light winds. Cloud cover and strong winds can lead to warmer overnight low temperatures.

During the afternoon, the sun beams down radiation to the surface. This warms the ground and the air where we live and breathe.

At night, with no more incoming radiation, the warm air leaves the ground and goes up into the air, escaping into space on a clear night. This leads to cool nights, especially when the season is right. If there are clouds at night, the outgoing radiation (heat) will get trapped by the clouds, which act like a blanket. The keeps some of the warm air near the ground limiting overnight cooling.

Wind also plays a role in how cool or warm your night can be. With light winds, you can expect a cooler night, but if it is windy overnight, expect overnight cooling to be limited. Strong winds move around the air. The turbulent air will stay warm because of friction. More air particles bouncing and rubbing off of each other.

You need to remember to cover the plants. Last night wasn't so bad. We had a light freeze in the valley but it only lasted a few hours. So if you forgot to cover the plants, and they are still doing fine, then definitley cover them tonight. We have another freeze warning in parts of the valley tonight.

At night, heat leaves plants and the ground, so by covering up your plants, you can trap the heat and keep them above the freezing level. Covering them with a type of fabric will also allow moisture to leave on the exterior of the plant and prevent that moisture from freezing and killing the plant.

As for what to do for you home, with a light freeze, you won't have much to worry about. However, if it drops below 30 degrees for an extended period of time, you'll want to cover your pipes outside and keep your indoor faucets at a drip to keep water flowing and prevent it from freezing and bursting your pipes indoors.

Chico
Partly Cloudy
54° wxIcon
Hi: 84° Lo: 48°
Feels Like: 54°
Oroville
Clear
52° wxIcon
Hi: 83° Lo: 58°
Feels Like: 52°
Chico
Clear
54° wxIcon
Hi: 78° Lo: 53°
Feels Like: 54°
Red Bluff
Clear
62° wxIcon
Hi: 61° Lo: 25°
Feels Like: 62°
Red Bluff
Clear
62° wxIcon
Hi: 83° Lo: 54°
Feels Like: 62°
Chico
Clear
54° wxIcon
Hi: 86° Lo: 56°
Feels Like: 54°
Dry weather, sunny skies, warmer temperatures, and gusty north winds will drive elevated fire danger today. We'll have even stronger winds, but cooler temperatures on Tuesday. Fire danger will remain elevated. There will also be a chance for light showers in the Sierra on Tuesday and Wednesday.
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