August is one of the warmer months of the year in Pasadena, with average highs near 32.4°C and lows around 26°C (mean 29.2°C). It is a relatively wet time of year, averaging 135 mm of rainfall and 75% relative humidity across the period.
August is one of the warmer months of the year in Pasadena. Across 45 years of records, the warmest August in Pasadena was 2023 — when the month averaged 32.7°C — while the coldest was 1992 at 27°C. Typical August days reach 32.4°C with nights near 26°C. The long-term trend is warming, about 0.4°C per decade.
August is a relatively wet time of year in Pasadena, averaging 135 mm of rainfall. The wettest August on record was 2017 with 997 mm, while the driest was 2023 at 7 mm.
Relative humidity in Pasadena during August averages 75%. The most humid August was 1983 at 83%, and the least humid was 2023 at 62%.
August receives about 5.9 kWh/m²/day of solar energy in Pasadena. The sunniest August was 2023 at 7 kWh/m²/day, and the cloudiest were 2016 and 2017 at 5.1.
Average wind speed in Pasadena during August is 2.6 m/s. The windiest August was 2017 at 3.5 m/s, while the calmest was 1991 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 28.6°C | 28.8°C | 29.0°C | 29.8°C | 30.3°C | +1.7°C |
| Avg High | 31.7°C | 31.9°C | 32.0°C | 33.1°C | 33.7°C | +2°C |
| Avg Low | 25.5°C | 25.8°C | 25.9°C | 26.4°C | 26.9°C | +1.4°C |
| Avg Rain | 129 mm | 103 mm | 137 mm | 193 mm | 95 mm | -34 mm |
August temperatures in Pasadena have risen by about 1.7°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 19.3°C (1992) to a record high of 41.1°C (2023).
Rainfall in August is a relatively wet time of year, averaging 135 mm, with a wettest year of 997 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.5°C per decade while lows rose 0.3°C per decade, widening the gap between day and night.
A quieter season to visit Pasadena
If your dates are flexible, the more temperate months of April and October tend to be the most comfortable for visiting Pasadena. That said, August — with days averaging 32.4°C and nights around 26°C (mean 29.2°C) and higher rainfall (135 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 33.7°C | 30.2°C | 26.7°C | 35.9°C | 25.0°C | 136 mm | 72% | 2.1 m/s | 5.4 |
| 2024 | 33.0°C | 29.9°C | 26.8°C | 36.3°C | 25.1°C | 74 mm | 76% | 2.2 m/s | 5.8 |
| 2023 🔥 | 37.4°C | 32.7°C | 28.0°C | 41.1°C | 25.2°C | 7 mm | 62% | 3.3 m/s | 7 |
| 2022 | 32.5°C | 29.7°C | 26.8°C | 35.5°C | 25.4°C | 190 mm | 77% | 2.8 m/s | 5.3 |
| 2021 | 32.1°C | 29.3°C | 26.5°C | 34.3°C | 25.3°C | 111 mm | 77% | 2.4 m/s | 5.8 |
| 2020 | 33.7°C | 30.0°C | 26.3°C | 35.7°C | 23.3°C | 54 mm | 71% | 2.8 m/s | 6.4 |
| 2019 | 33.9°C | 30.5°C | 27.2°C | 36.6°C | 25.6°C | 93 mm | 73% | 2.5 m/s | 5.6 |
| 2018 | 33.2°C | 29.8°C | 26.4°C | 36.1°C | 23.4°C | 65 mm | 73% | 2.8 m/s | 6 |
| 2017 🌧️ | 31.3°C | 28.8°C | 26.2°C | 33.7°C | 21.5°C | 997 mm | 80% | 3.5 m/s | 5.1 |
| 2016 | 31.1°C | 28.7°C | 26.3°C | 34.0°C | 24.6°C | 275 mm | 81% | 2.5 m/s | 5.1 |
| 2015 | 33.1°C | 29.4°C | 25.8°C | 36.6°C | 21.8°C | 124 mm | 73% | 2.4 m/s | 6.1 |
| 2014 | 32.7°C | 29.4°C | 26.1°C | 34.9°C | 22.8°C | 108 mm | 74% | 2.9 m/s | 5.6 |
| 2013 | 33.2°C | 29.6°C | 26.0°C | 36.0°C | 23.7°C | 84 mm | 72% | 2.8 m/s | 6.1 |
| 2012 | 32.8°C | 29.4°C | 26.1°C | 34.9°C | 23.9°C | 113 mm | 74% | 3 m/s | 6.3 |
| 2011 | 36.1°C | 31.7°C | 27.2°C | 39.2°C | 25.7°C | 17 mm | 64% | 2.9 m/s | 6.8 |
| 2010 | 33.8°C | 30.2°C | 26.6°C | 35.8°C | 23.6°C | 56 mm | 73% | 2.5 m/s | 6.3 |
| 2009 | 33.0°C | 29.7°C | 26.4°C | 35.4°C | 24.3°C | 90 mm | 72% | 2.6 m/s | 6 |
| 2008 | 31.3°C | 28.4°C | 25.5°C | 34.8°C | 24.2°C | 214 mm | 79% | 2.5 m/s | 5.5 |
| 2007 | 31.0°C | 28.5°C | 26.0°C | 34.5°C | 24.8°C | 162 mm | 82% | 2.3 m/s | 5.7 |
| 2006 | 31.2°C | 28.6°C | 26.1°C | 32.9°C | 22.1°C | 90 mm | 79% | 2.3 m/s | 5.9 |
| 2005 | 32.9°C | 29.8°C | 26.7°C | 35.3°C | 24.7°C | 66 mm | 73% | 2.1 m/s | 5.8 |
| 2004 | 31.5°C | 28.3°C | 25.1°C | 33.9°C | 20.5°C | 57 mm | 74% | 2.8 m/s | 6 |
| 2003 | 31.9°C | 28.9°C | 25.8°C | 36.8°C | 23.1°C | 161 mm | 77% | 2.5 m/s | 5.7 |
| 2002 | 31.1°C | 28.5°C | 25.8°C | 34.0°C | 23.5°C | 244 mm | 80% | 2.8 m/s | 5.7 |
| 2001 | 31.6°C | 28.8°C | 25.9°C | 35.0°C | 24.6°C | 249 mm | 77% | 2.8 m/s | 5.4 |
| 2000 | 34.1°C | 30.1°C | 26.1°C | 40.7°C | 24.1°C | 33 mm | 68% | 2.7 m/s | 6.4 |
| 1999 | 34.1°C | 30.1°C | 26.2°C | 37.2°C | 22.7°C | 30 mm | 71% | 2.7 m/s | 6.4 |
| 1998 | 32.4°C | 29.4°C | 26.4°C | 37.5°C | 24.9°C | 155 mm | 75% | 2.5 m/s | 5.5 |
| 1997 | 33.0°C | 29.6°C | 26.1°C | 35.4°C | 23.2°C | 44 mm | 72% | 2.9 m/s | 6.3 |
| 1996 | 30.8°C | 28.3°C | 25.9°C | 35.4°C | 23.9°C | 261 mm | 77% | 2.8 m/s | 5.3 |
| 1995 | 31.7°C | 29.0°C | 26.3°C | 34.6°C | 25.0°C | 99 mm | 76% | 2.4 m/s | 5.8 |
| 1994 | 30.7°C | 28.0°C | 25.3°C | 33.7°C | 23.7°C | 170 mm | 78% | 2.5 m/s | 5.5 |
| 1993 | 33.2°C | 29.8°C | 26.3°C | 35.5°C | 25.5°C | 51 mm | 72% | 2.7 m/s | 6.1 |
| 1992 ❄️ | 30.0°C | 27.0°C | 24.0°C | 33.8°C | 19.3°C | 72 mm | 76% | 2.3 m/s | 6 |
| 1991 | 30.2°C | 27.8°C | 25.4°C | 32.7°C | 24.2°C | 106 mm | 80% | 2 m/s | 5.8 |
| 1990 | 33.2°C | 29.4°C | 25.7°C | 36.9°C | 23.2°C | 42 mm | 70% | 2.5 m/s | 6.1 |
| 1989 | 29.7°C | 27.2°C | 24.7°C | 31.4°C | 19.4°C | 118 mm | 80% | 2.7 m/s | 5.9 |
| 1988 | 32.6°C | 29.3°C | 25.9°C | 37.3°C | 24.5°C | 78 mm | 75% | 2.7 m/s | 5.9 |
| 1987 | 31.9°C | 28.9°C | 26.0°C | 34.1°C | 24.1°C | 71 mm | 77% | 2.7 m/s | 6.3 |
| 1986 | 32.2°C | 28.6°C | 25.1°C | 37.3°C | 20.9°C | 119 mm | 72% | 2.8 m/s | 5.7 |
| 1985 | 32.8°C | 29.1°C | 25.3°C | 35.2°C | 24.2°C | 81 mm | 74% | 2.7 m/s | 6.5 |
| 1984 | 31.7°C | 28.5°C | 25.2°C | 35.7°C | 23.9°C | 110 mm | 74% | 2.8 m/s | 5.7 |
| 1983 | 30.1°C | 27.7°C | 25.4°C | 32.2°C | 24.3°C | 281 mm | 83% | 2.5 m/s | — |
| 1982 | 33.0°C | 29.6°C | 26.1°C | 35.0°C | 25.0°C | 76 mm | 72% | 2.8 m/s | — |
| 1981 | 31.7°C | 28.7°C | 25.8°C | 33.8°C | 22.7°C | 228 mm | 75% | 2.6 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 32.4°C with lows near 26°C (mean 29.2°C), based on 45 years of NASA POWER data.
August averages 135 mm of rainfall in Pasadena, a relatively wet time of year. The wettest on record was 997 mm in 2017.
The hottest August reached 41.1°C in 2023. The coldest dipped to 19.3°C in 1992.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.7°C. Daytime highs moved from 31.9°C to 33.7°C and overnight lows from 25.6°C to 27°C over the same span.
August is one of the warmer months of the year in Pasadena and a relatively wet time of year, so plan for around 32.4°C daytime highs and 26°C at night.
Not quite — August is the 12th coolest month in Pasadena, averaging 29.2°C.
For August in Pasadena, pack light, breathable clothing and sun protection, with typical highs of 32.4°C and lows of 26°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 75% — moderately humid.
Average wind speed in August is 2.6 m/s. The windiest August on record averaged 3.5 m/s (2017).
The wettest August on record was 2017 with 997 mm. On average, August sees 135 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 Pasadena 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.
