In August, Napa typically sees daytime highs of 29.5°C and overnight lows around 11.6°C. Compared to the annual average high of 21.5°C, August runs +8.0°C.
August in Napa averages a daytime high of 29.5°C and an overnight low of 11.6°C.
August runs +8.0°C compared to Napa's annual average high of 21.5°C, ranking #2 of 12 months by warmth.
Plan for daytime highs near 29.5°C and cooler evenings around 11.6°C.