Napa Valley 2021 Vintage at a Glance
This 2021 Napa Valley vintage chart depicts the high and low temperatures for each day of the growing season, as well as yearly rainfall and key stages of the growing season.
Temperature fluctuations have a significant effect on grapevines and grape development and therefore influence the character of the vintage. Tracking key stages of the growing season plays an important role in planning the logistics of the season and of harvest.
For example, many growers compare the date of bloom to growing season data from previous years to determine a timeframe for the first day of harvest. Rainfall affects this vintage and others by the way it indicates water storage in the soil and in underground aquifers.
Data for Oakville, CA courtesy U.C. Cooperative Extension, U.C. Davis and Napa Valley Winegrowers.