Napa weather in August 2025

Expect daytime maximum temperatures of 28°C in Napa, California in August based on long-term weather averages. There are 11 hours of sunshine per day on average.

  • 28°C maximum daytime temperature in August in Napa28
    28°C max day temperature
  • 11 hours of sunshine per day
  • 1 day with some rainfall in August in Napa1
    1 day with some rainfall
  • 12°C minimum night-time temperature in August in Napa12
    12°C min night temperature
  • 14 hours of daylight per day in August in Napa14
    14 hours of daylight per day
  • Moderate heat & humidity in August in NapaM
    Moderate heat & humidity
  • 3 mm monthly rainfall in August in Napa3
    3 mm of monthly rainfall
  • UV (maximum) index 9 (Very High) in August in Napa9
    9 (Very High) UV index

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The August weather guide for California (Napa) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm)  |  Imperial (°F / inches)

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How hot is it in Napa in August?

Daytime temperatures usually reach 28°C in Napa in August with moderate heat and humidity, falling to 12°C at night.

How sunny is it in Napa in August?

There are normally 11 hours of bright sunshine each day in Napa in August - that's 79% of daylight hours.

Does it ever rain in Napa in August?

There is usually 1 day with some rain in Napa in August and the average monthly rainfall is 3mm.

Napa August sunrise & sunset times

Browse the sunrise and sunset times for Napa in August 2025. Select a month to view Napa sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Friday, 1st August 2025 05:12 19:18
Saturday, 16th August 2025 05:25 19:01
Sunday, 31st August 2025 05:38 18:40

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