September is one of the cooler months of the year in Waiuku, with average highs near 15.5°C and lows around 10.4°C (mean 13°C). It is about average for rainfall, averaging 88 mm of rainfall and 81% relative humidity across the period.
September is one of the cooler months of the year in Waiuku. Across 45 years of records, the warmest September in Waiuku was 2005 — when the month averaged 14°C — while the coldest was 1992 at 11°C. Typical September days reach 15.5°C with nights near 10.4°C. The long-term September temperature trend is broadly flat.
September is about average for rainfall in Waiuku, averaging 88 mm of rainfall. The wettest September on record was 1997 with 166 mm, while the driest was 1993 at 7 mm.
Relative humidity in Waiuku during September averages 81%. The most humid September was 2016 at 85%, and the least humid was 1993 at 75%.
September receives about 4 kWh/m²/day of solar energy in Waiuku. The sunniest Septembers were 2018, 2019 and 2020, among others at 4.3 kWh/m²/day, and the cloudiest was 2016 at 3.5.
Average wind speed in Waiuku during September is 4.9 m/s. The windiest September was 1981 at 6.3 m/s, while the calmest was 2006 at 3.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.9°C | 12.4°C | 13.2°C | 12.9°C | 13.3°C | +0.4°C |
| Avg High | 15.4°C | 15.0°C | 15.9°C | 15.4°C | 15.7°C | +0.3°C |
| Avg Low | 10.5°C | 10.0°C | 10.5°C | 10.5°C | 10.8°C | +0.3°C |
| Avg Rain | 81 mm | 84 mm | 63 mm | 107 mm | 118 mm | +37 mm |
September temperatures in Waiuku have risen by about 0.6°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 4.4°C (1989) to a record high of 20.5°C (2023).
Rainfall in September is about average for rainfall, averaging 88 mm, with a wettest year of 166 mm.
A quieter season to visit Waiuku
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Waiuku. That said, September — with days averaging 15.5°C and nights around 10.4°C (mean 13°C) and higher rainfall (88 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 | 15.7°C | 13.5°C | 11.2°C | 18.7°C | 7.3°C | 119 mm | 82% | 5.6 m/s | 4 |
| 2024 | 15.7°C | 13.2°C | 10.7°C | 18.5°C | 7.7°C | 80 mm | 82% | 5.1 m/s | 4.1 |
| 2023 | 16.2°C | 13.8°C | 11.3°C | 20.5°C | 7.8°C | 152 mm | 85% | 5.2 m/s | 4.1 |
| 2022 | 15.9°C | 13.6°C | 11.2°C | 19.1°C | 7.6°C | 148 mm | 79% | 3.9 m/s | 4.2 |
| 2021 | 15.4°C | 12.8°C | 10.3°C | 18.5°C | 7.7°C | 151 mm | 81% | 5.1 m/s | 4 |
| 2020 | 15.5°C | 12.7°C | 10.0°C | 19.5°C | 5.1°C | 60 mm | 79% | 5.2 m/s | 4.3 |
| 2019 | 15.6°C | 13.1°C | 10.7°C | 17.6°C | 8.0°C | 111 mm | 82% | 5.1 m/s | 4.3 |
| 2018 | 15.4°C | 12.9°C | 10.4°C | 19.0°C | 8.1°C | 41 mm | 81% | 4.5 m/s | 4.3 |
| 2017 | 15.4°C | 13.2°C | 10.9°C | 18.4°C | 8.2°C | 116 mm | 83% | 5.1 m/s | 4.2 |
| 2016 | 15.9°C | 13.5°C | 11.0°C | 18.0°C | 6.2°C | 150 mm | 85% | 4.6 m/s | 3.5 |
| 2015 | 14.6°C | 12.2°C | 9.8°C | 17.2°C | 7.6°C | 115 mm | 81% | 4.4 m/s | 4.2 |
| 2014 | 15.5°C | 13.0°C | 10.5°C | 17.5°C | 6.0°C | 161 mm | 84% | 5 m/s | 3.9 |
| 2013 | 15.4°C | 13.0°C | 10.6°C | 18.0°C | 5.2°C | 113 mm | 83% | 5.3 m/s | 3.8 |
| 2012 | 15.3°C | 12.9°C | 10.4°C | 19.1°C | 5.4°C | 94 mm | 79% | 5.6 m/s | 4.1 |
| 2011 | 14.8°C | 12.2°C | 9.7°C | 16.9°C | 7.1°C | 70 mm | 77% | 4.6 m/s | 4.2 |
| 2010 | 15.6°C | 13.2°C | 10.8°C | 18.6°C | 8.0°C | 97 mm | 83% | 6 m/s | 3.7 |
| 2009 | 16.4°C | 13.4°C | 10.4°C | 19.3°C | 4.4°C | 75 mm | 82% | 4.1 m/s | 4.1 |
| 2008 | 15.8°C | 13.2°C | 10.5°C | 18.2°C | 8.6°C | 28 mm | 82% | 4.5 m/s | 4.2 |
| 2007 | 15.9°C | 13.2°C | 10.5°C | 18.1°C | 6.7°C | 45 mm | 81% | 4 m/s | 4.1 |
| 2006 | 16.2°C | 13.4°C | 10.7°C | 19.1°C | 7.7°C | 44 mm | 83% | 3.8 m/s | 4.2 |
| 2005 🔥 | 16.7°C | 14.0°C | 11.4°C | 19.3°C | 7.9°C | 75 mm | 81% | 4.6 m/s | 3.9 |
| 2004 | 14.6°C | 12.0°C | 9.4°C | 17.1°C | 5.5°C | 64 mm | 80% | 5.3 m/s | 3.9 |
| 2003 | 15.8°C | 13.3°C | 10.9°C | 19.3°C | 7.9°C | 131 mm | 84% | 5.8 m/s | 3.7 |
| 2002 | 15.6°C | 13.0°C | 10.4°C | 18.2°C | 6.5°C | 58 mm | 80% | 5.2 m/s | 4 |
| 2001 | 16.4°C | 13.6°C | 10.8°C | 19.5°C | 8.4°C | 61 mm | 80% | 3.9 m/s | 4.3 |
| 2000 | 15.9°C | 13.1°C | 10.3°C | 18.3°C | 6.2°C | 52 mm | 79% | 4.9 m/s | 4.1 |
| 1999 | 16.2°C | 13.3°C | 10.4°C | 18.1°C | 6.4°C | 42 mm | 80% | 4.1 m/s | 4.2 |
| 1998 | 16.2°C | 13.6°C | 11.0°C | 18.8°C | 8.2°C | 43 mm | 80% | 4.9 m/s | 3.8 |
| 1997 🌧️ | 14.4°C | 12.2°C | 10.0°C | 16.7°C | 6.3°C | 166 mm | 84% | 5 m/s | 3.6 |
| 1996 | 16.0°C | 13.4°C | 10.8°C | 17.9°C | 7.2°C | 115 mm | 84% | 4.5 m/s | 4 |
| 1995 | 15.4°C | 12.8°C | 10.2°C | 19.1°C | 5.8°C | 70 mm | 82% | 4.4 m/s | 4.1 |
| 1994 | 14.3°C | 11.9°C | 9.6°C | 16.5°C | 7.5°C | 125 mm | 81% | 6.2 m/s | 3.9 |
| 1993 | 14.2°C | 11.5°C | 8.9°C | 17.2°C | 4.5°C | 7 mm | 75% | 5.3 m/s | 4 |
| 1992 ❄️ | 13.4°C | 11.0°C | 8.7°C | 15.2°C | 5.4°C | 91 mm | 83% | 4.8 m/s | 3.9 |
| 1991 | 14.9°C | 12.8°C | 10.7°C | 17.4°C | 8.0°C | 100 mm | 83% | 4.9 m/s | 4.1 |
| 1990 | 14.5°C | 11.9°C | 9.4°C | 16.4°C | 6.3°C | 81 mm | 77% | 3.9 m/s | 4.3 |
| 1989 | 16.4°C | 13.7°C | 11.0°C | 19.0°C | 4.4°C | 80 mm | 82% | 4.4 m/s | 4 |
| 1988 | 15.8°C | 13.5°C | 11.1°C | 18.5°C | 6.7°C | 84 mm | 85% | 5 m/s | 3.7 |
| 1987 | 14.8°C | 12.8°C | 10.7°C | 17.9°C | 8.7°C | 137 mm | 81% | 6 m/s | 4 |
| 1986 | 14.7°C | 12.3°C | 9.9°C | 17.3°C | 6.6°C | 64 mm | 83% | 5.1 m/s | 4 |
| 1985 | 15.3°C | 13.0°C | 10.7°C | 18.3°C | 8.8°C | 78 mm | 80% | 6 m/s | 4.3 |
| 1984 | 15.6°C | 12.7°C | 9.9°C | 17.4°C | 6.7°C | 83 mm | 81% | 4.2 m/s | 4.2 |
| 1983 | 15.8°C | 13.1°C | 10.4°C | 18.3°C | 6.8°C | 73 mm | 82% | 5.3 m/s | — |
| 1982 | 15.6°C | 12.8°C | 9.9°C | 18.6°C | 5.8°C | 42 mm | 79% | 3.9 m/s | — |
| 1981 | 14.6°C | 12.5°C | 10.5°C | 18.2°C | 7.7°C | 92 mm | 81% | 6.3 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 15.5°C with lows near 10.4°C (mean 13°C), based on 45 years of NASA POWER data.
September averages 88 mm of rainfall in Waiuku, about average for rainfall. The wettest on record was 166 mm in 1997.
The hottest September reached 20.5°C in 2023. The coldest dipped to 4.4°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.6°C. Daytime highs moved from 15.4°C to 15.8°C and overnight lows from 10.3°C to 10.9°C over the same span.
September is one of the cooler months of the year in Waiuku and about average for rainfall, so plan for around 15.5°C daytime highs and 10.4°C at night.
Not quite — September is the 4th coolest month in Waiuku, averaging 13°C.
For September in Waiuku, pack light layers you can adjust through the day, with typical highs of 15.5°C and lows of 10.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 81% — quite humid.
Average wind speed in September is 4.9 m/s. The windiest September on record averaged 6.3 m/s (1981).
The wettest September on record was 1997 with 166 mm. On average, September sees 88 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 Waiuku 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.
