January is one of the warmer months of the year in Whanganui, with average highs near 21.3°C and lows around 14.6°C (mean 18°C). It is one of the drier months, averaging 65 mm of rainfall and 76% relative humidity across the period.
January is one of the warmer months of the year in Whanganui. Across 45 years of records, the warmest January in Whanganui was 2018 — when the month averaged 20.9°C — while the coldest was 1993 at 15.6°C. Typical January days reach 21.3°C with nights near 14.6°C. The long-term January temperature trend is broadly flat.
January is one of the drier months in Whanganui, averaging 65 mm of rainfall. The wettest January on record was 2023 with 209 mm, while the driest was 1988 at 11 mm.
Relative humidity in Whanganui during January averages 76%. The most humid January was 2023 at 84%, and the least humid was 2013 at 71%.
January receives about 6.5 kWh/m²/day of solar energy in Whanganui. The sunniest January was 2022 at 7.7 kWh/m²/day, and the cloudiest was 2023 at 5.3.
Average wind speed in Whanganui during January is 4.6 m/s. The windiest January was 2017 at 6.3 m/s, while the calmest was 2018 at 3.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 18.3°C | 17.6°C | 17.9°C | 18.1°C | 17.9°C | -0.4°C |
| Avg High | 21.8°C | 20.8°C | 21.3°C | 21.4°C | 21.2°C | -0.6°C |
| Avg Low | 14.9°C | 14.3°C | 14.4°C | 14.8°C | 14.6°C | -0.3°C |
| Avg Rain | 66 mm | 75 mm | 50 mm | 66 mm | 72 mm | +6 mm |
January temperatures in Whanganui have risen by about 0.3°C between 1981–1985 and 2021–2025.
January has ranged from a record low of 8.6°C (1995) to a record high of 30.2°C (2008).
Rainfall in January is one of the drier months, averaging 65 mm, with a wettest year of 209 mm.
One of the best times to visit Whanganui
January is one of the best times to visit Whanganui. Expect days averaging 21.3°C and nights around 14.6°C (mean 18°C) — warmer than Whanganui's yearly average — with moderate rainfall (65 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 | 20.0°C | 16.7°C | 13.3°C | 25.5°C | 10.5°C | 64 mm | 76% | 3.9 m/s | 6.4 |
| 2024 | 22.7°C | 19.4°C | 16.0°C | 26.7°C | 12.2°C | 60 mm | 77% | 4.1 m/s | 6.3 |
| 2023 🌧️ | 21.3°C | 18.2°C | 15.1°C | 24.1°C | 11.8°C | 209 mm | 84% | 3.7 m/s | 5.3 |
| 2022 | 22.0°C | 18.5°C | 14.9°C | 26.2°C | 11.6°C | 14 mm | 76% | 3.7 m/s | 7.7 |
| 2021 | 20.5°C | 17.6°C | 14.7°C | 23.6°C | 10.7°C | 61 mm | 79% | 4.6 m/s | 6.6 |
| 2020 | 20.7°C | 17.2°C | 13.7°C | 23.5°C | 9.6°C | 25 mm | 77% | 5 m/s | 7.3 |
| 2019 | 22.1°C | 19.1°C | 16.1°C | 27.0°C | 13.5°C | 35 mm | 79% | 5.3 m/s | 6.9 |
| 2018 🔥 | 24.1°C | 20.9°C | 17.6°C | 27.8°C | 11.7°C | 126 mm | 80% | 3.4 m/s | 6 |
| 2017 | 19.5°C | 16.6°C | 13.7°C | 21.6°C | 9.3°C | 76 mm | 78% | 6.3 m/s | 6.3 |
| 2016 | 22.2°C | 18.7°C | 15.1°C | 26.0°C | 9.6°C | 82 mm | 77% | 4.4 m/s | 6.4 |
| 2015 | 23.1°C | 19.3°C | 15.4°C | 26.1°C | 13.0°C | 15 mm | 71% | 3.8 m/s | 7.4 |
| 2014 | 20.0°C | 16.7°C | 13.4°C | 23.3°C | 10.2°C | 56 mm | 74% | 5.7 m/s | 6.6 |
| 2013 | 21.9°C | 18.2°C | 14.5°C | 26.8°C | 11.2°C | 34 mm | 71% | 5 m/s | 7.3 |
| 2012 | 19.8°C | 16.8°C | 13.8°C | 22.5°C | 10.4°C | 69 mm | 79% | 4.8 m/s | 5.7 |
| 2011 | 21.1°C | 17.8°C | 14.5°C | 27.4°C | 11.2°C | 98 mm | 77% | 5 m/s | 6.7 |
| 2010 | 19.8°C | 16.8°C | 13.8°C | 24.6°C | 10.6°C | 71 mm | 79% | 4.4 m/s | 6 |
| 2009 | 21.1°C | 17.6°C | 14.1°C | 25.3°C | 11.4°C | 40 mm | 76% | 4.6 m/s | 7.1 |
| 2008 | 23.1°C | 19.1°C | 15.1°C | 30.2°C | 10.3°C | 27 mm | 72% | 4.4 m/s | 7.1 |
| 2007 | 20.0°C | 16.9°C | 13.8°C | 25.2°C | 9.2°C | 53 mm | 81% | 4.2 m/s | 6 |
| 2006 | 21.7°C | 18.2°C | 14.8°C | 26.8°C | 11.5°C | 62 mm | 74% | 5.3 m/s | 6.2 |
| 2005 | 20.6°C | 17.3°C | 13.9°C | 26.3°C | 10.4°C | 47 mm | 79% | 4.5 m/s | 6.9 |
| 2004 | 22.4°C | 18.9°C | 15.3°C | 26.3°C | 12.3°C | 76 mm | 78% | 4.2 m/s | 6.6 |
| 2003 | 20.9°C | 17.4°C | 13.9°C | 26.3°C | 9.8°C | 30 mm | 73% | 4.9 m/s | 6.5 |
| 2002 | 21.6°C | 18.3°C | 15.1°C | 25.9°C | 10.6°C | 56 mm | 74% | 4.1 m/s | 6.2 |
| 2001 | 20.7°C | 17.3°C | 13.8°C | 24.1°C | 10.4°C | 29 mm | 72% | 5 m/s | 6.6 |
| 2000 | 21.0°C | 17.5°C | 14.0°C | 25.9°C | 10.6°C | 83 mm | 74% | 4.4 m/s | 5.9 |
| 1999 | 23.9°C | 20.0°C | 16.1°C | 26.2°C | 12.9°C | 69 mm | 73% | 4 m/s | 6.7 |
| 1998 | 20.9°C | 17.7°C | 14.5°C | 24.8°C | 9.9°C | 40 mm | 76% | 4.8 m/s | 6.1 |
| 1997 | 19.5°C | 16.2°C | 12.8°C | 22.5°C | 9.0°C | 101 mm | 78% | 4.1 m/s | 6.4 |
| 1996 | 21.3°C | 18.3°C | 15.3°C | 23.8°C | 12.1°C | 93 mm | 81% | 3.7 m/s | 6 |
| 1995 | 20.9°C | 17.5°C | 14.1°C | 24.3°C | 8.6°C | 81 mm | 78% | 3.9 m/s | 6.4 |
| 1994 | 21.4°C | 18.0°C | 14.7°C | 24.5°C | 10.8°C | 46 mm | 76% | 5 m/s | 6.4 |
| 1993 ❄️ | 18.3°C | 15.6°C | 12.8°C | 20.8°C | 10.0°C | 59 mm | 80% | 5.3 m/s | 6.4 |
| 1992 | 20.5°C | 17.3°C | 14.2°C | 24.2°C | 9.1°C | 80 mm | 79% | 4.1 m/s | 6.2 |
| 1991 | 20.3°C | 17.3°C | 14.2°C | 25.2°C | 10.8°C | 105 mm | 77% | 5 m/s | 6.1 |
| 1990 | 21.2°C | 17.7°C | 14.2°C | 26.2°C | 11.8°C | 72 mm | 76% | 4.6 m/s | 6.3 |
| 1989 | 23.4°C | 19.8°C | 16.2°C | 26.2°C | 12.4°C | 78 mm | 72% | 4.1 m/s | 6.1 |
| 1988 | 21.5°C | 17.9°C | 14.2°C | 25.5°C | 10.4°C | 11 mm | 73% | 4.8 m/s | 7.1 |
| 1987 | 22.4°C | 18.8°C | 15.1°C | 25.0°C | 11.2°C | 81 mm | 72% | 4.8 m/s | 6.6 |
| 1986 | 22.6°C | 19.5°C | 16.4°C | 26.4°C | 11.0°C | 127 mm | 79% | 4.1 m/s | 6 |
| 1985 | 22.8°C | 19.3°C | 15.9°C | 26.1°C | 13.8°C | 111 mm | 74% | 4.5 m/s | 6.5 |
| 1984 | 20.4°C | 16.7°C | 13.0°C | 24.7°C | 9.2°C | 44 mm | 71% | 4.9 m/s | 6.6 |
| 1983 | 18.7°C | 15.8°C | 12.9°C | 23.6°C | 10.1°C | 72 mm | 77% | 6.1 m/s | — |
| 1982 | 21.6°C | 18.1°C | 14.7°C | 25.3°C | 11.6°C | 40 mm | 73% | 5.5 m/s | — |
| 1981 | 23.0°C | 19.2°C | 15.5°C | 26.7°C | 10.5°C | 34 mm | 75% | 4.1 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 21.3°C with lows near 14.6°C (mean 18°C), based on 45 years of NASA POWER data.
January averages 65 mm of rainfall in Whanganui, one of the drier months. The wettest on record was 209 mm in 2023.
The hottest January reached 30.2°C in 2008. The coldest dipped to 8.6°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 0.3°C. Daytime highs moved from 21.3°C to 21.3°C and overnight lows from 14.4°C to 14.8°C over the same span.
January is one of the warmer months of the year in Whanganui and one of the drier months, so plan for around 21.3°C daytime highs and 14.6°C at night.
Not quite — January is the 11th coolest month in Whanganui, averaging 18°C.
For January in Whanganui, pack light layers you can adjust through the day, with typical highs of 21.3°C and lows of 14.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 76% — quite humid.
Average wind speed in January is 4.6 m/s. The windiest January on record averaged 6.3 m/s (2017).
The wettest January on record was 2023 with 209 mm. On average, January sees 65 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 January, 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 January specifically, along with year-by-year records and how the month has changed over the decades.
