Your Crops Are Colder Than You (And It’s Not The Jacket)
Hot air rises and cool air falls. Its kind of remarkable how much our lives as we know it depend on this, as this property of physics is one reason we have weather at all. During the winter, the thing to watch out for whenever the mercury dips is to see if the weather vane is standing still. When wind speeds are between 5 and 10 miles per hour or higher, warm and cold air masses get mixed together. When wind speeds are below 5 or 7 miles per hour however, those air masses can separate with cold air settling down at ground level, where your crops live. Weather forecasts give temperatures as they will be 6 ft above the ground, where you live.
The above chart shows the temperature at 6 ft and 2 ft on the night of January 10-11, 2017, when wind speeds struggled to break above 3mph. At 5:00AM, the temperature at 2 ft was nearly 2.5 degrees colder than the forecast temperature. Obviously on that night it didn’t matter, because temps were in the high 40’s. But 2.5 degrees is also the difference between 31 degrees and 28.5 degrees. This doesn’t mean you should be panicking when you see a forecast low of 34 a week out, but it does mean that you should have your cold protection plan ready to go just in case. And do keep an eye on the forecast. While we’re looking at very warm temperatures this week, it’s still only February, and March just LOVES to throw out one last cold punch before spring.