A warm weekend is on tap as the west coast ridge of high pressure strengthens through Sunday. Mostly sunny skies and valley highs in the low 80s will continue until Monday when a few clouds will move into the region, and a slow cooling trend begins. Highs drop to the upper 70s Monday to the upper 60s by Friday with a slight chance of a few showers by then.

tomato-blanket

We’ve been talking about how putting a tarp or a blanket over your tomato plants could keep them from freezing. But here’s a question that a surprisingly large number of people get wrong: Let’s say you take a thermometer and wrap it in a heavy blanket, and put it in an unheated garage overnight right next to an identical thermometer outside of the blanket. How much higher will the thermometer inside the blanket read in the morning than the one on the outside? Any guesses?

thermometers

Alright… here’s the answer: Not any higher at all. A blanket will not warm up a thermometer unless you heat up the blanket beforehand, and then only for a short period of time. So why do we feel warmer if we get under a down comforter?

blanket-baby

A blanket is an insulator. It is designed to prevent heat transfer from you to the outside world. We are endothermic (heat generating) creatures, and if we can keep the energy we create from being lost to the air around us, the temperature inside the blanket will rise. But if you wrap an inanimate object (like a thermometer) that doesn’t generate any heat in an insulator, unless it’s a perfect insulator (and there’s no such thing), eventually the inside of the blanket will reach the temperature of the outside of the blanket.

Of course it works the other way around as well. In extreme heat conditions (Death Valley in July), a heavy coat can keep you cooler than if you were naked.

And you’ll avoid some very unpleasant sunburn

 

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