September is one of the cooler months of the year in Griffith, with average highs near 20.2°C and lows around 6.6°C (mean 13.4°C). It is about average for rainfall, averaging 35 mm of rainfall and 65% relative humidity across the period.
September is one of the cooler months of the year in Griffith. Across 45 years of records, the warmest September in Griffith was 2023 — when the month averaged 16.9°C — while the coldest was 1992 at 10.8°C. Typical September days reach 20.2°C with nights near 6.6°C. The long-term trend is warming, about 0.5°C per decade.
September is about average for rainfall in Griffith, averaging 35 mm of rainfall. The wettest September on record was 2016 with 122 mm, while the driest was 2017 at 1 mm.
Relative humidity in Griffith during September averages 65%. The most humid September was 2016 at 78%, and the least humid was 2017 at 48%.
September receives about 5 kWh/m²/day of solar energy in Griffith. The sunniest September was 2018 at 5.7 kWh/m²/day, and the cloudiest was 2016 at 4.2.
Average wind speed in Griffith during September is 2.7 m/s. The windiest September was 1996 at 3.3 m/s, while the calmest was 1995 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.5°C | 12.8°C | 14.0°C | 13.5°C | 14.4°C | +1.9°C |
| Avg High | 19.1°C | 19.3°C | 21.1°C | 20.4°C | 21.5°C | +2.4°C |
| Avg Low | 5.9°C | 6.3°C | 6.8°C | 6.6°C | 7.4°C | +1.5°C |
| Avg Rain | 33 mm | 52 mm | 26 mm | 32 mm | 29 mm | -4 mm |
September temperatures in Griffith have risen by about 2.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of -0.2°C (1995) to a record high of 37.7°C (2017).
Rainfall in September is about average for rainfall, averaging 35 mm, with a wettest year of 122 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.6°C per decade while lows rose 0.3°C per decade, widening the gap between day and night.
A quieter season to visit Griffith
If your dates are flexible, the more temperate months of March and November tend to be the most comfortable for visiting Griffith. That said, September — with days averaging 20.2°C and nights around 6.6°C (mean 13.4°C) and moderate rainfall (35 mm) — can still be rewarding for travellers who don't mind the cooler conditions, and often means fewer crowds.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 21.8°C | 14.8°C | 7.8°C | 29.1°C | 3.9°C | 34 mm | 60% | 2.8 m/s | 5 |
| 2024 | 21.4°C | 14.2°C | 7.1°C | 30.5°C | 1.1°C | 22 mm | 60% | 2.8 m/s | 5.1 |
| 2023 🔥 | 25.2°C | 16.9°C | 8.6°C | 35.8°C | 1.6°C | 3 mm | 50% | 2.4 m/s | 5.5 |
| 2022 | 18.4°C | 12.6°C | 6.9°C | 23.3°C | 2.8°C | 54 mm | 74% | 2.5 m/s | 4.4 |
| 2021 | 20.9°C | 13.8°C | 6.7°C | 27.8°C | 1.9°C | 32 mm | 62% | 2.9 m/s | 5 |
| 2020 | 21.2°C | 14.3°C | 7.5°C | 28.7°C | 1.9°C | 27 mm | 67% | 2.7 m/s | 5 |
| 2019 | 21.2°C | 13.9°C | 6.5°C | 28.2°C | 1.9°C | 10 mm | 58% | 2.8 m/s | 5.2 |
| 2018 | 21.4°C | 13.9°C | 6.3°C | 27.8°C | 1.6°C | 5 mm | 49% | 2.5 m/s | 5.7 |
| 2017 | 22.0°C | 14.4°C | 6.8°C | 37.7°C | 1.2°C | 1 mm | 48% | 3.2 m/s | 5.2 |
| 2016 🌧️ | 17.3°C | 12.3°C | 7.3°C | 22.2°C | 3.7°C | 122 mm | 78% | 2.9 m/s | 4.2 |
| 2015 | 19.3°C | 12.3°C | 5.4°C | 25.9°C | 1.8°C | 20 mm | 68% | 2.2 m/s | 5.5 |
| 2014 | 20.9°C | 13.9°C | 6.8°C | 27.6°C | 2.2°C | 27 mm | 64% | 2.6 m/s | 5.2 |
| 2013 | 22.7°C | 15.7°C | 8.7°C | 30.6°C | 3.9°C | 44 mm | 63% | 2.7 m/s | 5 |
| 2012 | 20.5°C | 13.2°C | 5.9°C | 30.9°C | -0.1°C | 7 mm | 60% | 2.7 m/s | 5.1 |
| 2011 | 20.7°C | 13.6°C | 6.6°C | 30.3°C | 1.4°C | 26 mm | 62% | 3 m/s | 4.9 |
| 2010 | 17.9°C | 11.9°C | 6.0°C | 23.2°C | 0.6°C | 58 mm | 76% | 2.6 m/s | 4.7 |
| 2009 | 21.5°C | 14.2°C | 6.9°C | 30.3°C | 3.3°C | 19 mm | 57% | 3.1 m/s | 5.1 |
| 2008 | 22.1°C | 14.3°C | 6.5°C | 31.2°C | 1.5°C | 22 mm | 55% | 2.7 m/s | 5.6 |
| 2007 | 21.4°C | 13.8°C | 6.2°C | 26.5°C | 3.7°C | 4 mm | 55% | 3 m/s | 5.3 |
| 2006 | 22.4°C | 15.0°C | 7.5°C | 29.9°C | 2.5°C | 17 mm | 54% | 2.5 m/s | 5.5 |
| 2005 | 19.1°C | 12.8°C | 6.5°C | 26.1°C | 1.8°C | 61 mm | 71% | 2.4 m/s | 4.7 |
| 2004 | 20.0°C | 13.1°C | 6.3°C | 30.4°C | 0.6°C | 19 mm | 68% | 2.2 m/s | 4.7 |
| 2003 | 19.4°C | 12.5°C | 5.6°C | 32.0°C | 0.8°C | 17 mm | 68% | 3 m/s | 5 |
| 2002 | 22.3°C | 14.6°C | 6.8°C | 29.8°C | 1.4°C | 33 mm | 49% | 3.1 m/s | 5 |
| 2001 | 22.4°C | 15.4°C | 8.4°C | 32.4°C | 2.6°C | 42 mm | 62% | 2.7 m/s | 4.7 |
| 2000 | 20.6°C | 13.9°C | 7.2°C | 26.8°C | 2.5°C | 29 mm | 70% | 2.6 m/s | 4.9 |
| 1999 | 21.7°C | 15.1°C | 8.5°C | 29.1°C | 2.4°C | 55 mm | 66% | 2.6 m/s | 4.9 |
| 1998 | 20.3°C | 13.9°C | 7.6°C | 27.5°C | 2.0°C | 94 mm | 73% | 2.7 m/s | 4.4 |
| 1997 | 19.8°C | 13.3°C | 6.9°C | 23.4°C | 4.0°C | 55 mm | 68% | 2.2 m/s | 4.7 |
| 1996 | 18.8°C | 12.3°C | 5.7°C | 29.0°C | 2.1°C | 42 mm | 66% | 3.3 m/s | 4.7 |
| 1995 | 19.9°C | 13.1°C | 6.3°C | 27.2°C | -0.2°C | 27 mm | 69% | 2.1 m/s | 4.8 |
| 1994 | 19.8°C | 12.1°C | 4.4°C | 28.6°C | 0.2°C | 13 mm | 53% | 2.8 m/s | 5.4 |
| 1993 | 19.0°C | 12.9°C | 6.7°C | 26.5°C | 1.8°C | 82 mm | 73% | 2.8 m/s | 4.6 |
| 1992 ❄️ | 16.6°C | 10.8°C | 5.0°C | 23.0°C | 0.8°C | 63 mm | 72% | 2.6 m/s | 4.7 |
| 1991 | 18.7°C | 12.3°C | 5.8°C | 25.9°C | 0.4°C | 46 mm | 67% | 2.8 m/s | 5.1 |
| 1990 | 18.6°C | 12.3°C | 6.1°C | 25.2°C | 2.6°C | 39 mm | 74% | 2.6 m/s | 5 |
| 1989 | 17.7°C | 11.4°C | 5.0°C | 24.8°C | 1.7°C | 17 mm | 76% | 2.5 m/s | 5.2 |
| 1988 | 19.8°C | 13.5°C | 7.1°C | 26.6°C | 1.3°C | 52 mm | 71% | 2.6 m/s | 5.1 |
| 1987 | 20.2°C | 13.0°C | 5.9°C | 30.7°C | 0.8°C | 23 mm | 66% | 2.4 m/s | 5.1 |
| 1986 | 18.9°C | 12.7°C | 6.6°C | 25.6°C | 2.9°C | 47 mm | 73% | 2.7 m/s | 4.7 |
| 1985 | 18.3°C | 11.8°C | 5.4°C | 27.2°C | 1.8°C | 39 mm | 70% | 2.4 m/s | 5.1 |
| 1984 | 17.4°C | 11.2°C | 5.0°C | 23.5°C | 0.0°C | 33 mm | 70% | 2.6 m/s | 4.7 |
| 1983 | 18.8°C | 12.4°C | 6.1°C | 25.2°C | 0.2°C | 33 mm | 76% | 2.7 m/s | — |
| 1982 | 20.1°C | 13.0°C | 5.8°C | 27.7°C | 0.0°C | 27 mm | 52% | 2.8 m/s | — |
| 1981 | 20.9°C | 13.7°C | 6.6°C | 30.5°C | 2.5°C | 29 mm | 70% | 2.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 20.2°C with lows near 6.6°C (mean 13.4°C), based on 45 years of NASA POWER data.
September averages 35 mm of rainfall in Griffith, about average for rainfall. The wettest on record was 122 mm in 2016.
The hottest September reached 37.7°C in 2017. The coldest dipped to -0.2°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.1°C. Daytime highs moved from 19.1°C to 21.5°C and overnight lows from 5.8°C to 7.4°C over the same span.
September is one of the cooler months of the year in Griffith and about average for rainfall, so plan for around 20.2°C daytime highs and 6.6°C at night.
Not quite — September is the 5th coolest month in Griffith, averaging 13.4°C.
For September in Griffith, pack warm layers and a jacket for chilly mornings, with typical highs of 20.2°C and lows of 6.6°C.
Relative humidity in September averages 65% — moderately humid.
Average wind speed in September is 2.7 m/s. The windiest September on record averaged 3.3 m/s (1996).
The wettest September on record was 2016 with 122 mm. On average, September sees 35 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 Griffith 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.
