August is one of the warmer months of the year in Santa Rosa, with average highs near 32.5°C and lows around 14.1°C (mean 23.3°C). It is one of the drier months, averaging 1 mm of rainfall and 46% relative humidity across the period.
August is one of the warmer months of the year in Santa Rosa. Across 45 years of records, the warmest August in Santa Rosa was 1996 — when the month averaged 25.4°C — while the coldest was 2010 at 21.2°C. Typical August days reach 32.5°C with nights near 14.1°C. The long-term August temperature trend is broadly flat.
August is one of the drier months in Santa Rosa, averaging 1 mm of rainfall. The wettest August on record was 1997 with 17 mm, while the driest were 2017, 2018 and 2021, among others at 0 mm.
Relative humidity in Santa Rosa during August averages 46%. The most humid August was 1997 at 55%, and the least humid was 1996 at 37%.
August receives about 7 kWh/m²/day of solar energy in Santa Rosa. The sunniest Augusts were 2011 and 2025 at 7.4 kWh/m²/day, and the cloudiest was 2021 at 6.4.
Average wind speed in Santa Rosa during August is 1.8 m/s. The windiest Augusts were 2015, 2016 and 2024 at 2 m/s, while the calmest was 1998 at 1.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 23.2°C | 23.6°C | 23.1°C | 22.7°C | 24.1°C | +0.9°C |
| Avg High | 32.6°C | 32.9°C | 32.4°C | 31.7°C | 33.1°C | +0.5°C |
| Avg Low | 13.9°C | 14.3°C | 13.8°C | 13.6°C | 15.1°C | +1.2°C |
| Avg Rain | 2 mm | 2 mm | 1 mm | 0 mm | 1 mm | -2 mm |
August temperatures in Santa Rosa have risen by about 0.6°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 8.7°C (2010) to a record high of 43.6°C (1990).
Rainfall in August is one of the drier months, averaging 1 mm, with a wettest year of 17 mm.
Daytime highs and overnight lows have shifted differently — highs fell about 0.1°C per decade while lows rose 0.1°C per decade, narrowing the gap between day and night.
One of the best times to visit Santa Rosa
August is one of the best times to visit Santa Rosa. Expect days averaging 32.5°C and nights around 14.1°C (mean 23.3°C) — warmer than Santa Rosa's yearly average — with low rainfall (1 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 33.6°C | 24.2°C | 14.9°C | 38.3°C | 10.8°C | 0 mm | 44% | 1.9 m/s | 7.4 |
| 2024 | 32.2°C | 23.5°C | 14.7°C | 38.3°C | 11.0°C | 2 mm | 45% | 2 m/s | 7.1 |
| 2023 | 33.1°C | 24.2°C | 15.4°C | 39.5°C | 11.9°C | 1 mm | 47% | 1.8 m/s | 6.9 |
| 2022 | 32.9°C | 23.9°C | 14.8°C | 40.2°C | 11.1°C | 0 mm | 46% | 1.9 m/s | 7.1 |
| 2021 | 32.8°C | 23.6°C | 14.4°C | 39.9°C | 8.8°C | 0 mm | 44% | 1.8 m/s | 6.4 |
| 2020 | 34.0°C | 25.3°C | 16.5°C | 41.4°C | 11.6°C | 2 mm | 42% | 1.7 m/s | 6.7 |
| 2019 | 33.3°C | 24.2°C | 15.1°C | 41.4°C | 11.4°C | 0 mm | 47% | 1.9 m/s | 7.3 |
| 2018 | 31.8°C | 22.8°C | 13.8°C | 38.5°C | 10.3°C | 0 mm | 49% | 1.7 m/s | 6.8 |
| 2017 | 33.4°C | 24.3°C | 15.3°C | 41.9°C | 10.3°C | 0 mm | 45% | 1.8 m/s | 6.8 |
| 2016 | 31.3°C | 22.0°C | 12.6°C | 35.6°C | 9.6°C | 0 mm | 49% | 2 m/s | 7.1 |
| 2015 | 30.9°C | 22.5°C | 14.0°C | 37.7°C | 11.5°C | 0 mm | 54% | 2 m/s | 6.9 |
| 2014 | 31.0°C | 22.4°C | 13.8°C | 39.0°C | 11.5°C | 0 mm | 54% | 1.8 m/s | 6.5 |
| 2013 | 30.9°C | 22.1°C | 13.3°C | 39.0°C | 10.5°C | 0 mm | 54% | 1.9 m/s | 7 |
| 2012 | 33.0°C | 23.4°C | 13.7°C | 38.8°C | 9.5°C | 0 mm | 43% | 1.9 m/s | 7.2 |
| 2011 | 31.2°C | 21.9°C | 12.6°C | 35.6°C | 10.1°C | 0 mm | 52% | 1.6 m/s | 7.4 |
| 2010 ❄️ | 30.3°C | 21.2°C | 12.0°C | 41.2°C | 8.7°C | 0 mm | 53% | 1.8 m/s | 7.2 |
| 2009 | 32.4°C | 23.1°C | 13.8°C | 39.9°C | 9.6°C | 0 mm | 47% | 1.8 m/s | 7.2 |
| 2008 | 33.5°C | 24.0°C | 14.6°C | 41.1°C | 10.4°C | 0 mm | 46% | 1.9 m/s | 7.3 |
| 2007 | 32.5°C | 23.1°C | 13.8°C | 38.2°C | 10.5°C | 0 mm | 50% | 1.8 m/s | 7.3 |
| 2006 | 31.2°C | 22.0°C | 12.8°C | 37.2°C | 10.1°C | 0 mm | 50% | 1.6 m/s | 7.3 |
| 2005 | 32.8°C | 23.6°C | 14.5°C | 37.3°C | 11.2°C | 0 mm | 45% | 1.7 m/s | 7.2 |
| 2004 | 32.5°C | 23.4°C | 14.3°C | 38.2°C | 11.2°C | 2 mm | 51% | 1.9 m/s | 7.1 |
| 2003 | 31.4°C | 22.5°C | 13.7°C | 37.6°C | 11.2°C | 6 mm | 53% | 1.8 m/s | 7.2 |
| 2002 | 33.0°C | 23.2°C | 13.4°C | 39.8°C | 9.5°C | 0 mm | 45% | 1.7 m/s | 7 |
| 2001 | 32.4°C | 23.0°C | 13.5°C | 38.7°C | 10.1°C | 3 mm | 50% | 1.8 m/s | 7.3 |
| 2000 | 32.0°C | 23.0°C | 14.0°C | 40.7°C | 11.1°C | 1 mm | 46% | 1.8 m/s | 7 |
| 1999 | 31.1°C | 22.5°C | 13.9°C | 39.7°C | 10.6°C | 1 mm | 50% | 1.8 m/s | 6.9 |
| 1998 | 35.1°C | 25.2°C | 15.3°C | 42.5°C | 9.9°C | 0 mm | 41% | 1.4 m/s | 7.2 |
| 1997 🌧️ | 31.1°C | 22.4°C | 13.7°C | 40.8°C | 11.2°C | 17 mm | 55% | 1.8 m/s | 7 |
| 1996 🔥 | 35.2°C | 25.4°C | 15.6°C | 41.8°C | 10.4°C | 1 mm | 37% | 1.6 m/s | 7.3 |
| 1995 | 32.9°C | 23.3°C | 13.8°C | 38.4°C | 9.8°C | 0 mm | 41% | 1.7 m/s | 7.2 |
| 1994 | 34.1°C | 23.7°C | 13.4°C | 39.7°C | 10.9°C | 0 mm | 42% | 1.6 m/s | 7.2 |
| 1993 | 32.1°C | 23.1°C | 14.1°C | 41.1°C | 10.7°C | 1 mm | 45% | 1.7 m/s | 7.1 |
| 1992 | 34.6°C | 25.1°C | 15.5°C | 39.7°C | 10.4°C | 0 mm | 39% | 1.7 m/s | 7.1 |
| 1991 | 30.8°C | 21.9°C | 12.9°C | 35.5°C | 10.0°C | 3 mm | 55% | 1.8 m/s | 6.8 |
| 1990 | 32.3°C | 23.7°C | 15.2°C | 43.6°C | 11.2°C | 1 mm | 47% | 1.8 m/s | 6.8 |
| 1989 | 31.1°C | 21.9°C | 12.7°C | 37.9°C | 9.6°C | 1 mm | 47% | 1.7 m/s | 7.1 |
| 1988 | 33.1°C | 23.6°C | 14.1°C | 40.9°C | 9.6°C | 0 mm | 44% | 1.8 m/s | 6.8 |
| 1987 | 33.0°C | 23.6°C | 14.2°C | 38.0°C | 9.7°C | 0 mm | 41% | 1.6 m/s | 7.1 |
| 1986 | 33.2°C | 23.5°C | 13.8°C | 37.3°C | 10.5°C | 0 mm | 42% | 1.5 m/s | 6.8 |
| 1985 | 32.0°C | 22.5°C | 13.0°C | 36.9°C | 9.6°C | 1 mm | 41% | 1.7 m/s | 6.7 |
| 1984 | 33.2°C | 23.7°C | 14.2°C | 39.6°C | 10.9°C | 5 mm | 42% | 1.8 m/s | 6.5 |
| 1983 | 30.9°C | 22.6°C | 14.3°C | 38.5°C | 10.9°C | 13 mm | 53% | 1.8 m/s | — |
| 1982 | 32.5°C | 23.5°C | 14.5°C | 39.4°C | 10.0°C | 1 mm | 41% | 1.8 m/s | — |
| 1981 | 34.6°C | 24.3°C | 14.1°C | 42.0°C | 10.0°C | 0 mm | 39% | 1.8 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 32.5°C with lows near 14.1°C (mean 23.3°C), based on 45 years of NASA POWER data.
August averages 1 mm of rainfall in Santa Rosa, one of the drier months. The wettest on record was 17 mm in 1997.
The hottest August reached 43.6°C in 1990. The coldest dipped to 8.7°C in 2010.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.6°C. Daytime highs moved from 32.6°C to 32.9°C and overnight lows from 14°C to 14.8°C over the same span.
August is one of the warmer months of the year in Santa Rosa and one of the drier months, so plan for around 32.5°C daytime highs and 14.1°C at night.
Not quite — August is the 12th coolest month in Santa Rosa, averaging 23.3°C.
For August in Santa Rosa, pack light, breathable clothing and sun protection, with typical highs of 32.5°C and lows of 14.1°C.
Relative humidity in August averages 46% — relatively dry.
Average wind speed in August is 1.8 m/s. The windiest August on record averaged 2 m/s (2015).
The wettest August on record was 1997 with 17 mm. On average, August sees 1 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Santa Rosa behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
