September is one of the warmer months of the year in Santa Barbara, with average highs near 25.8°C and lows around 16.9°C (mean 21.4°C). It is one of the drier months, averaging 6 mm of rainfall and 56% relative humidity across the period.
September is one of the warmer months of the year in Santa Barbara. Across 45 years of records, the warmest September in Santa Barbara was 1984 — when the month averaged 24.2°C — while the coldest was 1986 at 18.2°C. Typical September days reach 25.8°C with nights near 16.9°C. The long-term September temperature trend is broadly flat.
September is one of the drier months in Santa Barbara, averaging 6 mm of rainfall. The wettest September on record was 1983 with 57 mm, while the driest were 1995, 1996 and 2021, among others at 0 mm.
Relative humidity in Santa Barbara during September averages 56%. The most humid September was 2023 at 70%, and the least humid was 2009 at 49%.
September receives about 5.9 kWh/m²/day of solar energy in Santa Barbara. The sunniest September was 2004 at 6.4 kWh/m²/day, and the cloudiest was 1984 at 5.1.
Average wind speed in Santa Barbara during September is 2.6 m/s. The windiest September was 2013 at 3.1 m/s, while the calmest was 1991 at 1.9 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.2°C | 21.2°C | 21.2°C | 21.6°C | 21.7°C | +0.5°C |
| Avg High | 25.7°C | 25.6°C | 25.8°C | 26.1°C | 25.9°C | +0.2°C |
| Avg Low | 16.6°C | 16.8°C | 16.7°C | 17.2°C | 17.6°C | +1°C |
| Avg Rain | 15 mm | 4 mm | 3 mm | 4 mm | 7 mm | -8 mm |
September temperatures in Santa Barbara have stayed relatively stable across the record.
September has ranged from a record low of 10.4°C (2007) to a record high of 38.8°C (2020).
Rainfall in September is one of the drier months, averaging 6 mm, with a wettest year of 57 mm.
One of the best times to visit Santa Barbara
September is one of the best times to visit Santa Barbara. Expect days averaging 25.8°C and nights around 16.9°C (mean 21.4°C) — warmer than Santa Barbara's yearly average — with low rainfall (6 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 | 25.1°C | 21.6°C | 18.0°C | 28.6°C | 15.8°C | 14 mm | 69% | 2.6 m/s | 5.4 |
| 2024 | 25.5°C | 21.3°C | 17.2°C | 35.5°C | 12.8°C | 1 mm | 57% | 2.7 m/s | 6 |
| 2023 | 24.2°C | 20.2°C | 16.2°C | 29.8°C | 13.3°C | 2 mm | 70% | 2.9 m/s | 5.7 |
| 2022 | 27.3°C | 23.2°C | 19.1°C | 35.7°C | 13.9°C | 22 mm | 58% | 2.6 m/s | 5.8 |
| 2021 | 25.0°C | 20.7°C | 16.5°C | 29.7°C | 12.4°C | 0 mm | 57% | 2.2 m/s | 5.9 |
| 2020 | 28.1°C | 23.4°C | 18.7°C | 38.8°C | 15.8°C | 0 mm | 50% | 2.4 m/s | 5.5 |
| 2019 | 26.1°C | 21.7°C | 17.3°C | 31.6°C | 10.8°C | 1 mm | 56% | 2.8 m/s | 6.2 |
| 2018 | 25.3°C | 20.8°C | 16.3°C | 31.5°C | 13.3°C | 1 mm | 57% | 2.3 m/s | 6.1 |
| 2017 | 25.5°C | 21.3°C | 17.0°C | 34.8°C | 11.4°C | 9 mm | 62% | 2.8 m/s | 6 |
| 2016 | 25.8°C | 21.2°C | 16.6°C | 34.2°C | 12.5°C | 0 mm | 54% | 2.6 m/s | 6.1 |
| 2015 | 27.7°C | 23.4°C | 19.2°C | 31.7°C | 14.9°C | 26 mm | 58% | 2.4 m/s | 6 |
| 2014 | 26.3°C | 22.0°C | 17.8°C | 32.1°C | 13.7°C | 1 mm | 58% | 2.8 m/s | 6.2 |
| 2013 | 25.8°C | 21.2°C | 16.5°C | 30.0°C | 10.9°C | 0 mm | 55% | 3.1 m/s | 6.3 |
| 2012 | 27.0°C | 22.6°C | 18.3°C | 32.4°C | 14.4°C | 2 mm | 49% | 2.3 m/s | 6 |
| 2011 | 25.5°C | 21.1°C | 16.6°C | 33.4°C | 14.2°C | 3 mm | 56% | 2.1 m/s | 5.7 |
| 2010 | 25.7°C | 20.9°C | 16.1°C | 35.2°C | 11.5°C | 0 mm | 51% | 2.4 m/s | 6.2 |
| 2009 | 27.6°C | 23.0°C | 18.4°C | 33.4°C | 11.7°C | 0 mm | 49% | 2.5 m/s | 6.1 |
| 2008 | 26.5°C | 22.0°C | 17.5°C | 31.3°C | 13.9°C | 1 mm | 52% | 2.4 m/s | 6 |
| 2007 | 24.1°C | 19.7°C | 15.3°C | 34.9°C | 10.4°C | 7 mm | 61% | 2.9 m/s | 6.3 |
| 2006 | 25.5°C | 20.9°C | 16.3°C | 30.0°C | 11.5°C | 2 mm | 53% | 2.5 m/s | 6.2 |
| 2005 | 23.8°C | 19.2°C | 14.6°C | 30.4°C | 11.7°C | 5 mm | 58% | 2.6 m/s | 6.3 |
| 2004 | 26.6°C | 21.9°C | 17.3°C | 32.9°C | 11.5°C | 2 mm | 50% | 2.7 m/s | 6.4 |
| 2003 | 26.3°C | 21.7°C | 17.1°C | 31.0°C | 14.5°C | 1 mm | 55% | 2.4 m/s | 6 |
| 2002 | 26.0°C | 21.4°C | 16.8°C | 33.4°C | 12.5°C | 3 mm | 50% | 2.4 m/s | 5.8 |
| 2001 | 25.5°C | 21.1°C | 16.6°C | 30.8°C | 13.9°C | 0 mm | 57% | 2.6 m/s | 6 |
| 2000 | 25.6°C | 21.1°C | 16.7°C | 31.9°C | 13.5°C | 7 mm | 57% | 2.8 m/s | 6 |
| 1999 | 24.1°C | 19.8°C | 15.4°C | 30.6°C | 12.9°C | 4 mm | 59% | 2 m/s | 5.9 |
| 1998 | 24.5°C | 20.4°C | 16.4°C | 32.6°C | 12.8°C | 15 mm | 66% | 2.7 m/s | 5.5 |
| 1997 | 27.4°C | 23.0°C | 18.6°C | 31.0°C | 14.4°C | 4 mm | 56% | 2.7 m/s | 6 |
| 1996 | 24.6°C | 20.4°C | 16.1°C | 27.9°C | 12.3°C | 0 mm | 56% | 2.5 m/s | 6.2 |
| 1995 | 26.1°C | 21.6°C | 17.1°C | 30.4°C | 12.3°C | 0 mm | 50% | 2.9 m/s | 6.2 |
| 1994 | 24.7°C | 20.5°C | 16.3°C | 28.3°C | 12.3°C | 6 mm | 57% | 2.6 m/s | 5.8 |
| 1993 | 25.7°C | 21.1°C | 16.5°C | 32.6°C | 11.8°C | 0 mm | 53% | 2.5 m/s | 6.1 |
| 1992 | 26.6°C | 22.0°C | 17.4°C | 30.1°C | 13.3°C | 1 mm | 50% | 2.4 m/s | 6.1 |
| 1991 | 25.4°C | 21.2°C | 17.1°C | 30.8°C | 11.5°C | 1 mm | 55% | 1.9 m/s | 5.7 |
| 1990 | 26.5°C | 21.6°C | 16.8°C | 31.6°C | 14.2°C | 7 mm | 54% | 2.9 m/s | 6.1 |
| 1989 | 25.5°C | 20.6°C | 15.7°C | 30.5°C | 11.2°C | 10 mm | 51% | 2.8 m/s | 5.9 |
| 1988 | 26.2°C | 21.5°C | 16.9°C | 35.6°C | 12.6°C | 1 mm | 50% | 2.3 m/s | 5.7 |
| 1987 | 27.1°C | 22.1°C | 17.2°C | 33.9°C | 13.4°C | 1 mm | 50% | 2.6 m/s | 5.6 |
| 1986 ❄️ | 22.7°C | 18.2°C | 13.8°C | 31.2°C | 10.6°C | 22 mm | 61% | 3 m/s | 5.6 |
| 1985 | 23.7°C | 19.4°C | 15.0°C | 28.9°C | 11.7°C | 4 mm | 60% | 2.9 m/s | 5.6 |
| 1984 🔥 | 28.6°C | 24.2°C | 19.8°C | 33.6°C | 13.8°C | 8 mm | 53% | 2.3 m/s | 5.1 |
| 1983 🌧️ | 26.5°C | 22.5°C | 18.4°C | 31.9°C | 14.1°C | 57 mm | 55% | 2.5 m/s | — |
| 1982 | 25.0°C | 20.7°C | 16.4°C | 34.7°C | 11.1°C | 26 mm | 56% | 2.9 m/s | — |
| 1981 | 26.0°C | 21.3°C | 16.6°C | 31.2°C | 14.1°C | 4 mm | 50% | 2.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 25.8°C with lows near 16.9°C (mean 21.4°C), based on 45 years of NASA POWER data.
September averages 6 mm of rainfall in Santa Barbara, one of the drier months. The wettest on record was 57 mm in 1983.
The hottest September reached 38.8°C in 2020. The coldest dipped to 10.4°C in 2007.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have fallen by about 0.2°C — but days and nights have moved in opposite directions. Overnight lows rose from 17.2°C to 17.4°C while daytime highs eased from 26°C to 25.4°C, narrowing the gap between day and night.
September is one of the warmer months of the year in Santa Barbara and one of the drier months, so plan for around 25.8°C daytime highs and 16.9°C at night.
Not quite — September is the 10th coolest month in Santa Barbara, averaging 21.4°C.
For September in Santa Barbara, pack light layers you can adjust through the day, with typical highs of 25.8°C and lows of 16.9°C.
Relative humidity in September averages 56% — moderately humid.
Average wind speed in September is 2.6 m/s. The windiest September on record averaged 3.1 m/s (2013).
The wettest September on record was 1983 with 57 mm. On average, September sees 6 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 Barbara behaves each September, 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 September specifically, along with year-by-year records and how the month has changed over the decades.
