September is one of the cooler months of the year in Greymouth, with average highs near 11.6°C and lows around 6.5°C (mean 9.1°C). It is about average for rainfall, averaging 173 mm of rainfall and 85% relative humidity across the period.
September is one of the cooler months of the year in Greymouth. Across 45 years of records, the warmest September in Greymouth was 1989 — when the month averaged 10.4°C — while the coldest was 1994 at 7.4°C. Typical September days reach 11.6°C with nights near 6.5°C. The long-term September temperature trend is broadly flat.
September is about average for rainfall in Greymouth, averaging 173 mm of rainfall. The wettest September on record was 1995 with 542 mm, while the driest was 1997 at 55 mm.
Relative humidity in Greymouth during September averages 85%. The most humid September was 2010 at 89%, and the least humid was 1997 at 79%.
September receives about 3.2 kWh/m²/day of solar energy in Greymouth. The sunniest Septembers were 1984, 1989 and 2018 at 3.7 kWh/m²/day, and the cloudiest was 2010 at 2.6.
Average wind speed in Greymouth during September is 1.4 m/s. The windiest September was 2010 at 1.8 m/s, while the calmest were 1992, 2016 and 2018, among others at 1.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 9.2°C | 8.6°C | 9.2°C | 9.0°C | 9.3°C | +0.1°C |
| Avg High | 11.9°C | 11.1°C | 11.8°C | 11.6°C | 11.7°C | -0.2°C |
| Avg Low | 6.5°C | 6.1°C | 6.6°C | 6.4°C | 6.9°C | +0.4°C |
| Avg Rain | 182 mm | 185 mm | 149 mm | 159 mm | 206 mm | +24 mm |
September temperatures in Greymouth have risen by about 0.3°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 0.2°C (2007) to a record high of 17.6°C (1989).
Rainfall in September is about average for rainfall, averaging 173 mm, with a wettest year of 542 mm.
A quieter season to visit Greymouth
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Greymouth. That said, September — with days averaging 11.6°C and nights around 6.5°C (mean 9.1°C) and higher rainfall (173 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 | 11.1°C | 9.0°C | 6.9°C | 14.2°C | 3.7°C | 245 mm | 87% | 1.7 m/s | 3 |
| 2024 | 11.1°C | 9.0°C | 6.9°C | 14.3°C | 3.1°C | 245 mm | 88% | 1.5 m/s | 3.1 |
| 2023 | 12.7°C | 10.2°C | 7.7°C | 15.5°C | 4.2°C | 201 mm | 85% | 1.5 m/s | 3.1 |
| 2022 | 12.3°C | 9.5°C | 6.7°C | 16.4°C | 1.4°C | 122 mm | 83% | 1.2 m/s | 3.3 |
| 2021 | 11.3°C | 8.9°C | 6.4°C | 15.0°C | 2.9°C | 202 mm | 86% | 1.5 m/s | 3.2 |
| 2020 | 11.5°C | 9.1°C | 6.7°C | 13.7°C | 2.6°C | 220 mm | 86% | 1.6 m/s | 3.2 |
| 2019 | 11.3°C | 8.9°C | 6.4°C | 15.1°C | 1.8°C | 154 mm | 85% | 1.3 m/s | 3.1 |
| 2018 | 12.3°C | 9.3°C | 6.4°C | 15.1°C | 2.4°C | 78 mm | 83% | 1.1 m/s | 3.7 |
| 2017 | 11.9°C | 9.5°C | 7.2°C | 14.9°C | 3.4°C | 226 mm | 88% | 1.3 m/s | 2.9 |
| 2016 | 12.9°C | 10.0°C | 7.0°C | 16.4°C | 3.0°C | 143 mm | 84% | 1.1 m/s | 3.4 |
| 2015 | 11.0°C | 8.1°C | 5.2°C | 14.0°C | 1.4°C | 107 mm | 82% | 1.3 m/s | 3.6 |
| 2014 | 12.2°C | 9.4°C | 6.5°C | 15.3°C | 2.1°C | 148 mm | 85% | 1.2 m/s | 3.4 |
| 2013 | 11.8°C | 9.3°C | 6.8°C | 14.8°C | 3.2°C | 156 mm | 85% | 1.4 m/s | 3 |
| 2012 | 11.5°C | 9.0°C | 6.5°C | 15.3°C | 1.4°C | 211 mm | 86% | 1.5 m/s | 2.9 |
| 2011 | 10.8°C | 8.1°C | 5.5°C | 14.2°C | 2.4°C | 89 mm | 85% | 1.4 m/s | 3.3 |
| 2010 | 10.5°C | 8.3°C | 6.2°C | 14.1°C | 1.5°C | 282 mm | 89% | 1.8 m/s | 2.6 |
| 2009 | 11.7°C | 8.8°C | 6.0°C | 14.9°C | 0.6°C | 106 mm | 82% | 1.3 m/s | 3.6 |
| 2008 | 11.9°C | 9.3°C | 6.8°C | 14.9°C | 1.8°C | 120 mm | 86% | 1.3 m/s | 3 |
| 2007 | 12.2°C | 9.3°C | 6.5°C | 15.5°C | 0.2°C | 89 mm | 84% | 1.2 m/s | 3.5 |
| 2006 | 12.2°C | 9.8°C | 7.4°C | 14.1°C | 3.9°C | 137 mm | 86% | 1.3 m/s | 3.1 |
| 2005 | 12.4°C | 10.0°C | 7.6°C | 16.0°C | 1.5°C | 184 mm | 87% | 1.3 m/s | 3.1 |
| 2004 | 10.4°C | 8.0°C | 5.6°C | 13.1°C | 1.0°C | 196 mm | 87% | 1.6 m/s | 2.9 |
| 2003 | 11.0°C | 8.6°C | 6.3°C | 13.4°C | 2.5°C | 220 mm | 85% | 1.6 m/s | 2.8 |
| 2002 | 11.6°C | 9.2°C | 6.7°C | 13.6°C | 1.0°C | 209 mm | 87% | 1.6 m/s | 2.7 |
| 2001 | 13.0°C | 10.1°C | 7.2°C | 15.6°C | 3.8°C | 92 mm | 84% | 1.2 m/s | 3.3 |
| 2000 | 11.8°C | 9.0°C | 6.2°C | 14.1°C | 2.1°C | 134 mm | 84% | 1.3 m/s | 3.3 |
| 1999 | 12.6°C | 10.0°C | 7.4°C | 15.1°C | 2.3°C | 111 mm | 85% | 1.3 m/s | 3.3 |
| 1998 | 11.6°C | 9.3°C | 7.0°C | 14.7°C | 1.9°C | 147 mm | 86% | 1.5 m/s | 3.3 |
| 1997 | 11.5°C | 8.4°C | 5.2°C | 14.6°C | 1.1°C | 55 mm | 79% | 1.2 m/s | 3.5 |
| 1996 | 12.3°C | 9.9°C | 7.5°C | 16.1°C | 4.0°C | 241 mm | 87% | 1.3 m/s | 3.1 |
| 1995 🌧️ | 10.4°C | 8.4°C | 6.3°C | 13.4°C | 1.4°C | 542 mm | 88% | 1.4 m/s | 2.7 |
| 1994 ❄️ | 9.8°C | 7.4°C | 5.0°C | 12.0°C | 0.4°C | 196 mm | 86% | 1.4 m/s | 3.1 |
| 1993 | 10.4°C | 7.8°C | 5.3°C | 13.3°C | 1.1°C | 143 mm | 82% | 1.4 m/s | 3.4 |
| 1992 | 10.5°C | 7.6°C | 4.7°C | 13.0°C | 1.0°C | 98 mm | 82% | 1.1 m/s | 3.6 |
| 1991 | 11.3°C | 9.0°C | 6.8°C | 14.3°C | 2.5°C | 219 mm | 87% | 1.3 m/s | 3.2 |
| 1990 | 11.1°C | 8.5°C | 5.9°C | 13.2°C | 1.3°C | 97 mm | 84% | 1.2 m/s | 3.5 |
| 1989 🔥 | 13.9°C | 10.4°C | 7.0°C | 17.6°C | 1.1°C | 106 mm | 82% | 1.1 m/s | 3.7 |
| 1988 | 12.2°C | 10.0°C | 7.7°C | 15.6°C | 3.9°C | 251 mm | 88% | 1.2 m/s | 2.9 |
| 1987 | 11.3°C | 8.9°C | 6.4°C | 14.1°C | 3.7°C | 214 mm | 87% | 1.5 m/s | 2.9 |
| 1986 | 11.3°C | 8.7°C | 6.1°C | 13.8°C | 3.2°C | 163 mm | 83% | 1.3 m/s | 3.4 |
| 1985 | 12.3°C | 9.3°C | 6.4°C | 15.3°C | 1.8°C | 193 mm | 84% | 1.4 m/s | 3.5 |
| 1984 | 12.6°C | 9.3°C | 6.0°C | 14.8°C | 1.9°C | 122 mm | 83% | 1.2 m/s | 3.7 |
| 1983 | 11.3°C | 9.0°C | 6.7°C | 14.9°C | 3.8°C | 206 mm | 88% | 1.5 m/s | — |
| 1982 | 11.6°C | 8.9°C | 6.2°C | 14.1°C | 2.1°C | 174 mm | 84% | 1.2 m/s | — |
| 1981 | 10.6°C | 8.4°C | 6.2°C | 12.9°C | 0.9°C | 213 mm | 87% | 1.7 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 11.6°C with lows near 6.5°C (mean 9.1°C), based on 45 years of NASA POWER data.
September averages 173 mm of rainfall in Greymouth, about average for rainfall. The wettest on record was 542 mm in 1995.
The hottest September reached 17.6°C in 1989. The coldest dipped to 0.2°C in 2007.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.3°C. Daytime highs moved from 11.7°C to 11.7°C and overnight lows from 6.3°C to 6.9°C over the same span.
September is one of the cooler months of the year in Greymouth and about average for rainfall, so plan for around 11.6°C daytime highs and 6.5°C at night.
Not quite — September is the 4th coolest month in Greymouth, averaging 9.1°C.
For September in Greymouth, pack warm layers and a jacket for chilly mornings, with typical highs of 11.6°C and lows of 6.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 85% — quite humid.
Average wind speed in September is 1.4 m/s. The windiest September on record averaged 1.8 m/s (2010).
The wettest September on record was 1995 with 542 mm. On average, September sees 173 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 Greymouth 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.
