Table 1.
Site conditions at two commercial vineyards in Fresno County and Napa County from experimental years (2019–2021) and long-term mean values (2011–2021).
| Year | Air temperature (°C) | Soil temperature (°C) | Precipitation (mm)b | GDD (°C) | ||||
|---|---|---|---|---|---|---|---|---|
| Daily max | Daily min | Daily average | Daily max | Daily min | Daily average | |||
| Fresno County (Five points) | ||||||||
| 2020 | ||||||||
| Mean | 25.6 | 9.1 | 17.3 | 25.7 | 10.7 | 22.6 | 199 | 2,358 |
| Annual maxa | 35.8 | 18 | 27.3 | -- | -- | -- | -- | -- |
| Annual mina | 15.6 | 0.6 | 7.6 | -- | -- | -- | -- | -- |
| 2021 | ||||||||
| Mean | 25.8 | 9.2 | 17.6 | 26.6 | 10.4 | 22.8 | 152.5 | 2,488 |
| Annual max | 37.8 | 18.7 | 28.5 | -- | -- | -- | -- | -- |
| Annual min | 12.5 | 3.1 | 7.7 | -- | -- | -- | -- | -- |
| 2011–2021 | ||||||||
| Mean | 25.4 | 9.4 | 17.2 | 25.6 | 10.1 | 22.3 | 209.6 | 2,259 |
| Napa County (Oakville) | ||||||||
| 2020 | ||||||||
| Mean | 24.4 | 7 | 14.9 | 22.5 | 10 | 16.5 | 234.2 | 1,647 |
| Annual max | 31.8 | 12.3 | 21.1 | -- | -- | -- | -- | -- |
| Annual min | 17.1 | 2 | 8.5 | -- | -- | -- | -- | -- |
| 2021 | ||||||||
| Mean | 23.1 | 6.3 | 14.2 | 22.8 | 10.2 | 16.4 | 278.3 | 1,519 |
| Annual max | 30 | 10.8 | 19.2 | -- | -- | -- | -- | -- |
| Annual min | 12.5 | 2.6 | 7.6 | -- | -- | -- | -- | -- |
| 2011–2021 | ||||||||
| Mean | 23.2 | 7.1 | 14.5 | 22.8 | 7.9 | 16 | 577.8 | 1,504 |
a Annual maximum (max) and annual minimum (min) indicate the greatest or lowest value observed during the respective year. b Total precipitation occurred during the annual winter rainy season, calculated from October of the preceding year through September of the following year (e.g., 2020 values were calculated from 1 October 2019 to 30 September 2020). c--, not applicable and GDD, growing degree days.