John Wheeler, Published September 10 2012
Weather Talk: First frost of fall may come without any actual crystalsThere has been very little dew this year. The atmosphere has had very low levels of humidity much of the time. Also, with the soil moisture so low, there has been less humidity in that layer of air right against the ground.
I bring this up because over the next few weeks we will likely experience our first frosts of fall. But if the weather remains this dry, then the first frost may come without frost. This can happen because the definition of a “frost” is a temperature of 32 degrees or lower, but if the ground and air are dry, then the temperature may drop below 32 degrees without there being any actual frost crystals. Sensitive plants are damaged or killed by the temperature, with or without the white stuff.
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