How do you know when spring has begun? Is it the appearance of the first tiny leaves on the trees, or the first crocus plants peeping through the snow? The First Leaf and First Bloom Indices are synthetic measures of these early season events in plants, based on recent temperature conditions. These models allow us to track the progression of spring onset across the country.
February 10, 2020
Spring leaf out has arrived in the Southeast, over three weeks earlier than a long-term average (1981-2010) in some locations. Charlottesville, VA is 24 days early, Knoxville, TN is 20 days early, and Nashville, TN is 18 days early.
despite that, we had a couple really warm days last week. Because of that, we have already accumulated 7-9 growing degree days in Cincinnati and 5 in Columbus. Silver maple comes into bloom at 34 degree days. This week is the coldest week of the winter. After this, we begin to slowly warm toward the first day of meteorological spring. We are already 7-9 growing degree days closer!