Napa County Historical Growing Degree Days (T>50ºF)
Seasonal comparison of GDD accumulation from April 1st through yesterday (6/29)
Courtesy of westernwx.com

Where is Napa Valley in terms of previous vintages as far as Growing Degree Days so far this year? Depending on where in the valley you are this year, you can be a little behind or a little ahead of previous years. What are “Growing Degree Days”? Basically, it is a way to track warm air temperature. Here’s an explanation.