I google the soil temperature. There are places that keep track of the soil temperatures and post them on-line, This is PROBABLY done for the convenience of the farmers.Do you monitor your soil's temperature? I'm in Texas and the weather changes frequently. We've had a few cold blasts and my veggies are in excellent condition. I monitor soil conditions along with average air temperatures. I've never made a mistake with this technique. I do the same thing every year. Have yet to lose a vegetable.