September is one of the cooler months of the year in Grafton, with average highs near 22.9°C and lows around 13.8°C (mean 18.4°C). It is one of the drier months, averaging 45 mm of rainfall and 68% relative humidity across the period.
September is one of the cooler months of the year in Grafton. Across 45 years of records, the warmest Septembers in Grafton were 2000 and 2003 — when the month averaged 20.4°C — while the coldest were 1984 and 1985 at 16.4°C. Typical September days reach 22.9°C with nights near 13.8°C. The long-term trend is warming, about 0.3°C per decade.
September is one of the drier months in Grafton, averaging 45 mm of rainfall. The wettest September on record was 1988 with 152 mm, while the driest was 1991 at 2 mm.
Relative humidity in Grafton during September averages 68%. The most humid September was 1983 at 79%, and the least humid was 1991 at 53%.
September receives about 5.3 kWh/m²/day of solar energy in Grafton. The sunniest September was 2003 at 6.1 kWh/m²/day, and the cloudiest was 2010 at 4.3.
Average wind speed in Grafton during September is 2.7 m/s. The windiest September was 2008 at 3.1 m/s, while the calmest was 1987 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.5°C | 17.9°C | 18.9°C | 18.6°C | 18.8°C | +1.3°C |
| Avg High | 22.0°C | 22.4°C | 23.6°C | 23.2°C | 23.2°C | +1.2°C |
| Avg Low | 12.9°C | 13.3°C | 14.2°C | 14.1°C | 14.4°C | +1.5°C |
| Avg Rain | 53 mm | 45 mm | 44 mm | 39 mm | 42 mm | -10 mm |
September temperatures in Grafton have risen by about 1.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 6.4°C (1987) to a record high of 34.9°C (2017).
Rainfall in September is one of the drier months, averaging 45 mm, with a wettest year of 152 mm.
One of the best times to visit Grafton
September is one of the best times to visit Grafton. Expect days averaging 22.9°C and nights around 13.8°C (mean 18.4°C) — cooler than Grafton's yearly average — with moderate rainfall (45 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 | 22.7°C | 18.3°C | 14.0°C | 28.9°C | 11.6°C | 12 mm | 75% | 2.5 m/s | 5.4 |
| 2024 | 24.2°C | 19.3°C | 14.5°C | 30.3°C | 11.4°C | 98 mm | 67% | 3 m/s | 5.2 |
| 2023 | 25.0°C | 20.2°C | 15.3°C | 32.2°C | 12.8°C | 7 mm | 59% | 2.8 m/s | 5.4 |
| 2022 | 21.2°C | 17.7°C | 14.1°C | 26.2°C | 11.9°C | 98 mm | 75% | 2.7 m/s | 4.7 |
| 2021 | 23.1°C | 18.4°C | 13.8°C | 28.7°C | 10.4°C | 19 mm | 65% | 3 m/s | 5.3 |
| 2020 | 23.1°C | 19.0°C | 14.9°C | 29.0°C | 10.4°C | 20 mm | 67% | 2.7 m/s | 5 |
| 2019 | 24.7°C | 19.6°C | 14.6°C | 30.6°C | 11.4°C | 11 mm | 60% | 2.6 m/s | 5.6 |
| 2018 | 22.0°C | 18.0°C | 14.0°C | 28.6°C | 11.5°C | 102 mm | 71% | 2.9 m/s | 5 |
| 2017 | 25.4°C | 19.7°C | 14.0°C | 34.9°C | 9.4°C | 5 mm | 60% | 2.5 m/s | 5.9 |
| 2016 | 22.8°C | 18.6°C | 14.5°C | 26.1°C | 11.3°C | 25 mm | 69% | 2.7 m/s | 4.6 |
| 2015 | 22.3°C | 18.0°C | 13.8°C | 27.0°C | 10.9°C | 39 mm | 67% | 2.8 m/s | 5.2 |
| 2014 | 21.3°C | 17.3°C | 13.3°C | 27.7°C | 9.2°C | 32 mm | 73% | 2.5 m/s | 5.3 |
| 2013 | 25.0°C | 19.9°C | 14.8°C | 32.4°C | 12.5°C | 36 mm | 65% | 2.6 m/s | 5.8 |
| 2012 | 23.4°C | 18.4°C | 13.4°C | 29.1°C | 9.0°C | 30 mm | 66% | 2.6 m/s | 5.7 |
| 2011 | 22.2°C | 17.6°C | 13.0°C | 28.7°C | 9.0°C | 29 mm | 68% | 2.6 m/s | 5.4 |
| 2010 | 23.1°C | 19.2°C | 15.2°C | 27.8°C | 12.3°C | 82 mm | 71% | 2.6 m/s | 4.3 |
| 2009 | 23.2°C | 18.4°C | 13.6°C | 28.5°C | 9.4°C | 51 mm | 70% | 2.5 m/s | 5.7 |
| 2008 | 22.6°C | 18.7°C | 14.8°C | 30.0°C | 11.4°C | 87 mm | 73% | 3.1 m/s | 5 |
| 2007 | 22.2°C | 17.9°C | 13.6°C | 28.3°C | 11.0°C | 47 mm | 74% | 2.8 m/s | 5.5 |
| 2006 | 21.5°C | 17.9°C | 14.3°C | 26.6°C | 11.2°C | 94 mm | 77% | 3 m/s | 5.4 |
| 2005 | 23.2°C | 18.6°C | 14.0°C | 29.9°C | 9.8°C | 57 mm | 69% | 2.8 m/s | 5 |
| 2004 | 23.7°C | 19.0°C | 14.3°C | 31.6°C | 10.1°C | 43 mm | 63% | 2.9 m/s | 5.5 |
| 2003 | 26.2°C | 20.4°C | 14.5°C | 34.8°C | 10.2°C | 6 mm | 54% | 2.8 m/s | 6.1 |
| 2002 | 25.0°C | 19.7°C | 14.5°C | 33.2°C | 11.3°C | 19 mm | 63% | 2.9 m/s | 5.4 |
| 2001 | 22.4°C | 18.3°C | 14.3°C | 27.1°C | 10.0°C | 26 mm | 69% | 2.6 m/s | 5 |
| 2000 🔥 | 26.2°C | 20.4°C | 14.5°C | 34.7°C | 10.5°C | 12 mm | 59% | 2.7 m/s | 5.5 |
| 1999 | 20.7°C | 17.4°C | 14.1°C | 25.5°C | 10.0°C | 58 mm | 78% | 2.4 m/s | 5.2 |
| 1998 | 22.7°C | 19.0°C | 15.3°C | 26.9°C | 11.9°C | 118 mm | 75% | 2.7 m/s | 4.7 |
| 1997 | 22.9°C | 18.5°C | 14.0°C | 29.7°C | 11.2°C | 60 mm | 68% | 2.8 m/s | 4.8 |
| 1996 | 22.7°C | 17.4°C | 12.0°C | 29.7°C | 8.7°C | 46 mm | 70% | 2.7 m/s | 5.5 |
| 1995 | 23.0°C | 18.4°C | 13.7°C | 27.8°C | 7.6°C | 34 mm | 67% | 2.7 m/s | 5.1 |
| 1994 | 23.3°C | 17.8°C | 12.2°C | 27.6°C | 8.6°C | 18 mm | 57% | 2.7 m/s | 5.8 |
| 1993 | 21.7°C | 17.6°C | 13.4°C | 28.9°C | 10.7°C | 37 mm | 67% | 2.9 m/s | 5.2 |
| 1992 | 23.1°C | 17.8°C | 12.4°C | 30.4°C | 8.9°C | 24 mm | 60% | 2.7 m/s | 5.3 |
| 1991 | 24.0°C | 18.4°C | 12.8°C | 29.3°C | 8.8°C | 2 mm | 53% | 2.6 m/s | 5.8 |
| 1990 | 20.2°C | 16.5°C | 12.9°C | 27.1°C | 8.9°C | 58 mm | 73% | 2.8 m/s | 5 |
| 1989 | 21.2°C | 16.5°C | 11.9°C | 26.4°C | 9.1°C | 14 mm | 70% | 2.7 m/s | 6 |
| 1988 🌧️ | 21.4°C | 17.8°C | 14.1°C | 25.9°C | 9.7°C | 152 mm | 79% | 2.9 m/s | 4.9 |
| 1987 | 21.1°C | 16.7°C | 12.3°C | 26.4°C | 6.4°C | 6 mm | 73% | 2.1 m/s | 5.7 |
| 1986 | 23.7°C | 18.9°C | 14.0°C | 30.1°C | 8.4°C | 21 mm | 63% | 2.9 m/s | 5.3 |
| 1985 | 20.4°C | 16.4°C | 12.5°C | 25.6°C | 8.7°C | 63 mm | 73% | 2.5 m/s | 5.4 |
| 1984 ❄️ | 21.5°C | 16.4°C | 11.3°C | 24.6°C | 8.9°C | 28 mm | 65% | 2.5 m/s | 5.8 |
| 1983 | 22.4°C | 18.0°C | 13.6°C | 27.3°C | 10.5°C | 57 mm | 79% | 2.7 m/s | — |
| 1982 | 22.0°C | 17.3°C | 12.7°C | 28.6°C | 9.1°C | 115 mm | 66% | 2.8 m/s | — |
| 1981 | 24.4°C | 19.3°C | 14.1°C | 32.8°C | 8.4°C | 19 mm | 65% | 2.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 22.9°C with lows near 13.8°C (mean 18.4°C), based on 45 years of NASA POWER data.
September averages 45 mm of rainfall in Grafton, one of the drier months. The wettest on record was 152 mm in 1988.
The hottest September reached 34.9°C in 2017. The coldest dipped to 6.4°C in 1987.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.3°C. Daytime highs moved from 22.1°C to 23.2°C and overnight lows from 12.8°C to 14.3°C over the same span.
September is one of the cooler months of the year in Grafton and one of the drier months, so plan for around 22.9°C daytime highs and 13.8°C at night.
Not quite — September is the 5th coolest month in Grafton, averaging 18.4°C.
For September in Grafton, pack light layers you can adjust through the day, with typical highs of 22.9°C and lows of 13.8°C.
Relative humidity in September averages 68% — moderately humid.
Average wind speed in September is 2.7 m/s. The windiest September on record averaged 3.1 m/s (2008).
The wettest September on record was 1988 with 152 mm. On average, September sees 45 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 Grafton 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.
