Napa weather in August: Napa, California: normal highs, lows, rain and records for August
Napa in August has a normal high of 80°F and a normal low of 54°F, a daily mean of 67°F, rising from 79°F on the 1st to 81°F by the 31st. Measurable precipitation falls on 0 days in a normal August, 0.02 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 27°C and low of 12°C, 1 mm of precipitation in August.
- NOAA stationNapa County Airport
- Station IDUSW00093227
- Location38.21°N 122.28°W
- Elevation14 ft (4 m)
- Population76,921
- Jan 57° 38°
- Feb 61° 40°
- Mar 64° 42°
- Apr 68° 44°
- May 73° 48°
- Jun 78° 52°
- Jul 79° 55°
- Aug 80° 54°
- Sep 80° 51°
- Oct 75° 46°
- Nov 65° 40°
- Dec 57° 38°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Napa in August?
The normal high is 80°F and the normal low 54°F, for a daily mean of 67.2°F. August is 0.5°F warmer than July and 1.5°F warmer than September. August is the warmest month of the year in Napa and the 11th wettest. Across the month the normal high rises 2°F, from 79°F on August 1 to 81°F on August 31. From one year to the next August's mean temperature typically moves about 1.4°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 66°F and 69°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 2%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 79°F | 55°F | 1% | 0% |
| August 8 | 79°F | 55°F | 1% | 0% |
| August 15 | 80°F | 55°F | 1% | 0% |
| August 22 | 81°F | 54°F | 1% | 0% |
| August 31 | 81°F | 53°F | 2% | 0% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 30, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 79°F | 55°F | 1% | 0% | 14 h 10 min |
| August 2 | 79°F | 55°F | 1% | 0% | 14 h 10 min |
| August 3 | 79°F | 55°F | 1% | 0% | 14 h 10 min |
| August 4 | 79°F | 55°F | 1% | 0% | 14 h |
| August 5 | 79°F | 55°F | 1% | 0% | 14 h |
| August 6 | 79°F | 55°F | 1% | 0% | 14 h |
| August 7 | 79°F | 55°F | 1% | 0% | 14 h |
| August 8 | 79°F | 55°F | 1% | 0% | 14 h |
| August 9 | 79°F | 55°F | 1% | 0% | 13 h 50 min |
| August 10 | 79°F | 55°F | 1% | 0% | 13 h 50 min |
| August 11 | 80°F | 55°F | 1% | 0% | 13 h 50 min |
| August 12 | 80°F | 55°F | 1% | 0% | 13 h 50 min |
| August 13 | 80°F | 55°F | 1% | 0% | 13 h 50 min |
| August 14 | 80°F | 55°F | 1% | 0% | 13 h 40 min |
| August 15 | 80°F | 55°F | 1% | 0% | 13 h 40 min |
| August 16 | 80°F | 55°F | 1% | 0% | 13 h 40 min |
| August 17 | 80°F | 54°F | 1% | 0% | 13 h 40 min |
| August 18 | 80°F | 54°F | 1% | 0% | 13 h 40 min |
| August 19 | 80°F | 54°F | 1% | 0% | 13 h 30 min |
| August 20 | 81°F | 54°F | 1% | 0% | 13 h 30 min |
| August 21 | 81°F | 54°F | 1% | 0% | 13 h 30 min |
| August 22 | 81°F | 54°F | 1% | 0% | 13 h 30 min |
| August 23 | 81°F | 54°F | 1% | 0% | 13 h 20 min |
| August 24 | 81°F | 54°F | 1% | 0% | 13 h 20 min |
| August 25 | 81°F | 54°F | 1% | 0% | 13 h 20 min |
| August 26 | 81°F | 54°F | 1% | 0% | 13 h 20 min |
| August 27 | 81°F | 54°F | 1% | 0% | 13 h 10 min |
| August 28 | 81°F | 53°F | 1% | 0% | 13 h 10 min |
| August 29 | 81°F | 53°F | 1% | 0% | 13 h 10 min |
| August 30 | 81°F | 53°F | 2% | 0% | 13 h 10 min |
| August 31 | 81°F | 53°F | 2% | 0% | 13 h 10 min |
- Normal high
- 80°FAugust average
- Normal low
- 54°FAugust average
- Precipitation
- 0.02 inmonth total
- Days with precipitation
- fewer than 10.01 inch or more
- Days at 90°F or more
- 3
- Daylight
- 14 h 10 min to 13 h 10 minAugust 1 to August 31
- Days at 70°F or more
- 30
- Days at 80°F or more
- 13
- Sunshine
- 94%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00093227; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Napa in August?
On a given August day the chance of 0.01 inch or more is 1% on average, highest around August 31 (2%). In all, 0.02 in falls on 0 days of a normal August.
In a normal August in Napa, 3 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00093227.
What are the records for August in Napa?
The warmest August temperature on this station's record (since 1998) is 106°F, on August 14, 2020; the coldest is 42°F, on August 31, 2008. The wettest August brought 0.30 in (2003).
The August mean against the 1991-2020 normal of 67.2°F: 2021 66.1°F (−1.1), 2022 69.3°F (+2.1), 2023 69.9°F (+2.7), 2024 66.9°F (−0.3), 2025 66.9°F (−0.3), 2026 65.6°F (−1.6). 2 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 66.1°F | −1.1°F | 0.00 in |
| 2022 | 69.3°F | +2.1°F | 0.01 in |
| 2023 | 69.9°F | +2.7°F | 0.00 in |
| 2024 | 66.9°F | −0.3°F | 0.00 in |
| 2025 | 66.9°F | −0.3°F | 0.00 in |
| 2026 | 65.6°F | −1.6°F | 0.00 in |
Source: records: ACIS, station USW00093227; recent months: ACIS, station USW00093227. Records and recent months use complete months only.
How does August in Napa compare across California?
Across the 219 places PlainClimate covers in California, August normal highs run from 63°F in Bodega to 109°F in Needles; Napa's is 80°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.