August is one of the cooler months of the year in Whanganui, with average highs near 12.6°C and lows around 7.7°C (mean 10.2°C). It is about average for rainfall, averaging 88 mm of rainfall and 85% relative humidity across the period.
August is one of the cooler months of the year in Whanganui. Across 45 years of records, the warmest August in Whanganui was 2013 — when the month averaged 11.5°C — while the coldest was 2004 at 8.9°C. Typical August days reach 12.6°C with nights near 7.7°C. The long-term August temperature trend is broadly flat.
August is about average for rainfall in Whanganui, averaging 88 mm of rainfall. The wettest August on record was 2008 with 155 mm, while the driest was 2005 at 26 mm.
Relative humidity in Whanganui during August averages 85%. The most humid August was 2017 at 87%, and the least humid was 1998 at 82%.
August receives about 2.5 kWh/m²/day of solar energy in Whanganui. The sunniest August was 2005 at 3.1 kWh/m²/day, and the cloudiest was 2010 at 2.2.
Average wind speed in Whanganui during August is 4.6 m/s. The windiest August was 2019 at 5.6 m/s, while the calmest was 1987 at 3.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 10.0°C | 9.7°C | 10.3°C | 10.4°C | 10.4°C | +0.4°C |
| Avg High | 12.6°C | 12.1°C | 12.7°C | 12.8°C | 12.9°C | +0.3°C |
| Avg Low | 7.5°C | 7.4°C | 7.9°C | 7.9°C | 7.9°C | +0.4°C |
| Avg Rain | 64 mm | 100 mm | 76 mm | 97 mm | 109 mm | +46 mm |
August temperatures in Whanganui have risen by about 0.3°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 2.7°C (1984) to a record high of 17.6°C (1989).
Rainfall in August is about average for rainfall, averaging 88 mm, with a wettest year of 155 mm.
A quieter season to visit Whanganui
If your dates are flexible, the more temperate months of February and January tend to be the most comfortable for visiting Whanganui. That said, August — with days averaging 12.6°C and nights around 7.7°C (mean 10.2°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 | 12.4°C | 9.7°C | 7.0°C | 15.4°C | 4.6°C | 70 mm | 84% | 4 m/s | 2.8 |
| 2024 | 13.2°C | 11.0°C | 8.7°C | 17.1°C | 4.7°C | 129 mm | 86% | 5.1 m/s | 2.3 |
| 2023 | 11.8°C | 9.4°C | 6.9°C | 14.5°C | 4.2°C | 102 mm | 85% | 4.1 m/s | 2.6 |
| 2022 | 13.5°C | 11.2°C | 8.9°C | 17.6°C | 4.5°C | 152 mm | 87% | 4.9 m/s | 2.5 |
| 2021 | 13.1°C | 10.4°C | 7.8°C | 15.4°C | 4.3°C | 121 mm | 84% | 5 m/s | 2.6 |
| 2020 | 13.2°C | 10.6°C | 8.0°C | 16.0°C | 3.1°C | 82 mm | 84% | 4.3 m/s | 2.6 |
| 2019 | 12.6°C | 10.5°C | 8.5°C | 14.3°C | 2.8°C | 108 mm | 83% | 5.6 m/s | 2.4 |
| 2018 | 13.3°C | 10.9°C | 8.4°C | 15.6°C | 5.2°C | 109 mm | 86% | 4 m/s | 2.5 |
| 2017 | 13.4°C | 10.9°C | 8.3°C | 16.1°C | 4.0°C | 131 mm | 87% | 4.7 m/s | 2.6 |
| 2016 | 12.4°C | 9.8°C | 7.2°C | 15.1°C | 3.5°C | 107 mm | 85% | 4.1 m/s | 2.8 |
| 2015 | 12.2°C | 9.7°C | 7.2°C | 14.8°C | 4.0°C | 102 mm | 86% | 4.6 m/s | 2.5 |
| 2014 | 12.3°C | 9.7°C | 7.0°C | 16.6°C | 4.4°C | 81 mm | 83% | 4.7 m/s | 2.7 |
| 2013 🔥 | 13.9°C | 11.5°C | 9.0°C | 16.2°C | 6.2°C | 62 mm | 85% | 4.5 m/s | 2.5 |
| 2012 | 13.4°C | 10.7°C | 8.0°C | 15.2°C | 5.1°C | 87 mm | 86% | 3.7 m/s | 2.5 |
| 2011 | 11.8°C | 9.4°C | 7.0°C | 16.7°C | 3.0°C | 64 mm | 86% | 4.1 m/s | 2.6 |
| 2010 | 13.1°C | 10.8°C | 8.5°C | 15.5°C | 5.2°C | 118 mm | 86% | 4.2 m/s | 2.2 |
| 2009 | 14.0°C | 11.2°C | 8.3°C | 17.1°C | 3.6°C | 83 mm | 84% | 4.8 m/s | 2.6 |
| 2008 🌧️ | 12.0°C | 10.0°C | 8.0°C | 14.8°C | 4.2°C | 155 mm | 85% | 4.9 m/s | 2.4 |
| 2007 | 12.5°C | 10.4°C | 8.4°C | 14.7°C | 5.3°C | 105 mm | 84% | 5.2 m/s | 2.4 |
| 2006 | 11.9°C | 9.6°C | 7.2°C | 14.3°C | 3.1°C | 104 mm | 85% | 4.5 m/s | 2.5 |
| 2005 | 13.9°C | 10.9°C | 7.9°C | 15.7°C | 4.6°C | 26 mm | 84% | 3.8 m/s | 3.1 |
| 2004 ❄️ | 11.1°C | 8.9°C | 6.7°C | 14.2°C | 3.5°C | 61 mm | 84% | 5.3 m/s | 2.6 |
| 2003 | 13.3°C | 10.7°C | 8.1°C | 15.6°C | 5.2°C | 29 mm | 84% | 4.4 m/s | 2.6 |
| 2002 | 12.5°C | 10.3°C | 8.1°C | 15.3°C | 5.4°C | 69 mm | 85% | 5 m/s | 2.3 |
| 2001 | 13.2°C | 10.8°C | 8.4°C | 16.3°C | 5.8°C | 72 mm | 85% | 5 m/s | 2.4 |
| 2000 | 12.8°C | 10.2°C | 7.6°C | 15.5°C | 4.8°C | 51 mm | 83% | 4 m/s | 2.6 |
| 1999 | 12.5°C | 9.8°C | 7.1°C | 14.6°C | 3.6°C | 68 mm | 83% | 4.3 m/s | 2.5 |
| 1998 | 12.5°C | 10.2°C | 7.8°C | 16.5°C | 3.9°C | 49 mm | 82% | 4.5 m/s | 2.5 |
| 1997 | 12.1°C | 9.7°C | 7.3°C | 15.6°C | 3.4°C | 60 mm | 85% | 5.4 m/s | 2.4 |
| 1996 | 11.6°C | 9.4°C | 7.2°C | 14.9°C | 2.8°C | 111 mm | 84% | 4.7 m/s | 2.4 |
| 1995 | 11.4°C | 9.1°C | 6.7°C | 13.3°C | 3.3°C | 123 mm | 84% | 4.8 m/s | 2.6 |
| 1994 | 12.3°C | 10.0°C | 7.7°C | 14.4°C | 3.7°C | 99 mm | 85% | 4.6 m/s | 2.5 |
| 1993 | 11.5°C | 9.0°C | 6.5°C | 13.0°C | 3.7°C | 73 mm | 84% | 4 m/s | 2.8 |
| 1992 | 11.0°C | 9.1°C | 7.2°C | 14.1°C | 4.1°C | 149 mm | 84% | 5.5 m/s | 2.3 |
| 1991 | 12.9°C | 10.7°C | 8.5°C | 15.7°C | 5.7°C | 130 mm | 86% | 5.2 m/s | 2.3 |
| 1990 | 12.7°C | 10.4°C | 8.0°C | 15.7°C | 4.6°C | 140 mm | 85% | 4.7 m/s | 2.5 |
| 1989 | 12.9°C | 10.0°C | 7.2°C | 17.6°C | 3.8°C | 65 mm | 85% | 4.2 m/s | 2.7 |
| 1988 | 12.8°C | 10.3°C | 7.9°C | 16.2°C | 4.9°C | 82 mm | 85% | 4.7 m/s | 2.5 |
| 1987 | 13.7°C | 11.2°C | 8.7°C | 16.5°C | 5.9°C | 44 mm | 85% | 3.6 m/s | 2.7 |
| 1986 | 11.5°C | 9.0°C | 6.5°C | 14.0°C | 3.0°C | 97 mm | 85% | 4 m/s | 2.8 |
| 1985 | 12.3°C | 9.6°C | 6.9°C | 15.3°C | 4.0°C | 71 mm | 84% | 4.3 m/s | 2.7 |
| 1984 | 13.6°C | 10.7°C | 7.9°C | 16.0°C | 2.7°C | 57 mm | 83% | 4.6 m/s | 2.6 |
| 1983 | 12.6°C | 10.1°C | 7.7°C | 15.3°C | 3.8°C | 41 mm | 85% | 4.2 m/s | — |
| 1982 | 12.6°C | 10.1°C | 7.5°C | 14.5°C | 2.9°C | 41 mm | 85% | 4.9 m/s | — |
| 1981 | 11.6°C | 9.4°C | 7.3°C | 14.7°C | 4.6°C | 77 mm | 85% | 4.3 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 12.6°C with lows near 7.7°C (mean 10.2°C), based on 45 years of NASA POWER data.
August averages 88 mm of rainfall in Whanganui, about average for rainfall. The wettest on record was 155 mm in 2008.
The hottest August reached 17.6°C in 1989. The coldest dipped to 2.7°C in 1984.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.3°C. Daytime highs moved from 12.5°C to 12.8°C and overnight lows from 7.5°C to 7.9°C over the same span.
August is one of the cooler months of the year in Whanganui and about average for rainfall, so plan for around 12.6°C daytime highs and 7.7°C at night.
Not quite — August is the 2nd coolest month in Whanganui, averaging 10.2°C.
For August in Whanganui, pack warm layers and a jacket for chilly mornings, with typical highs of 12.6°C and lows of 7.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 85% — quite humid.
Average wind speed in August is 4.6 m/s. The windiest August on record averaged 5.6 m/s (2019).
The wettest August on record was 2008 with 155 mm. On average, August 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 Whanganui behaves each August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
