January is one of the cooler months of the year in Hamilton, with average highs near 4.4°C and lows around 0.3°C (mean 2.4°C). It is about average for rainfall, averaging 90 mm of rainfall and 95% relative humidity across the period.
January is one of the cooler months of the year in Hamilton. Across 45 years of records, the warmest January in Hamilton was 1989 — when the month averaged 5.3°C — while the coldest was 1985 at -1.4°C. Typical January days reach 4.4°C with nights near 0.3°C. The long-term trend is warming, about 0.3°C per decade.
January is about average for rainfall in Hamilton, averaging 90 mm of rainfall. The wettest January on record was 2016 with 174 mm, while the driest was 2019 at 33 mm.
Relative humidity in Hamilton during January averages 95%. The most humid Januarys were 1997 and 2001 at 97%, and the least humid was 1993 at 93%.
January receives about 0.5 kWh/m²/day of solar energy in Hamilton. The sunniest Januarys were 2023, 2024 and 2025, among others at 0.6 kWh/m²/day, and the cloudiest were 2014, 2016 and 2020, among others at 0.4.
Average wind speed in Hamilton during January is 4.3 m/s. The windiest January was 1983 at 6.9 m/s, while the calmest was 1997 at 2.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 1.3°C | 2.5°C | 3.1°C | 2.1°C | 2.8°C | +1.5°C |
| Avg High | 3.4°C | 4.4°C | 5.1°C | 4.1°C | 4.8°C | +1.4°C |
| Avg Low | -0.7°C | 0.6°C | 1.0°C | 0.1°C | 0.8°C | +1.5°C |
| Avg Rain | 93 mm | 97 mm | 92 mm | 89 mm | 75 mm | -18 mm |
January temperatures in Hamilton have risen by about 1.7°C between 1981–1985 and 2021–2025.
January has ranged from a record low of -17.6°C (1982) to a record high of 11.3°C (2020).
Rainfall in January is about average for rainfall, averaging 90 mm, with a wettest year of 174 mm.
A quieter season to visit Hamilton
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Hamilton. That said, January — with days averaging 4.4°C and nights around 0.3°C (mean 2.4°C) and higher rainfall (90 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 | 4.4°C | 2.4°C | 0.5°C | 10.0°C | -4.5°C | 54 mm | 96% | 3.3 m/s | 0.6 |
| 2024 | 4.6°C | 2.6°C | 0.6°C | 10.6°C | -6.2°C | 86 mm | 95% | 4 m/s | 0.6 |
| 2023 | 5.4°C | 3.3°C | 1.2°C | 9.7°C | -4.0°C | 84 mm | 96% | 4.2 m/s | 0.6 |
| 2022 | 6.3°C | 4.1°C | 1.8°C | 11.2°C | -2.4°C | 48 mm | 95% | 4.4 m/s | 0.5 |
| 2021 | 1.9°C | 0.2°C | -1.6°C | 7.5°C | -7.4°C | 93 mm | 97% | 2.8 m/s | 0.6 |
| 2020 | 6.4°C | 4.3°C | 2.3°C | 11.3°C | -2.9°C | 84 mm | 95% | 5.2 m/s | 0.4 |
| 2019 | 4.2°C | 2.1°C | 0.0°C | 9.3°C | -3.2°C | 33 mm | 95% | 3.2 m/s | 0.6 |
| 2018 | 3.8°C | 2.0°C | 0.2°C | 9.7°C | -4.6°C | 111 mm | 96% | 4 m/s | 0.5 |
| 2017 | 4.8°C | 2.8°C | 0.8°C | 9.1°C | -3.6°C | 55 mm | 96% | 3.4 m/s | 0.5 |
| 2016 🌧️ | 4.3°C | 2.4°C | 0.5°C | 11.1°C | -4.5°C | 174 mm | 95% | 4.3 m/s | 0.4 |
| 2015 | 4.7°C | 2.5°C | 0.3°C | 11.0°C | -3.3°C | 105 mm | 93% | 5.5 m/s | 0.5 |
| 2014 | 4.9°C | 3.0°C | 1.2°C | 7.5°C | -1.7°C | 114 mm | 96% | 4.1 m/s | 0.4 |
| 2013 | 3.9°C | 2.2°C | 0.5°C | 9.5°C | -4.3°C | 98 mm | 96% | 3.9 m/s | 0.5 |
| 2012 | 5.4°C | 3.1°C | 0.8°C | 9.2°C | -2.1°C | 68 mm | 95% | 4.6 m/s | 0.5 |
| 2011 | 3.1°C | 1.1°C | -1.0°C | 9.5°C | -7.3°C | 74 mm | 96% | 3 m/s | 0.6 |
| 2010 | 1.6°C | -0.4°C | -2.4°C | 7.5°C | -8.0°C | 55 mm | 96% | 3.1 m/s | 0.6 |
| 2009 | 3.9°C | 2.0°C | 0.1°C | 9.0°C | -6.6°C | 85 mm | 96% | 4.1 m/s | 0.5 |
| 2008 | 5.5°C | 3.6°C | 1.7°C | 10.6°C | -2.8°C | 158 mm | 95% | 4.8 m/s | 0.4 |
| 2007 | 6.6°C | 4.4°C | 2.2°C | 10.6°C | -2.2°C | 111 mm | 94% | 5.5 m/s | 0.5 |
| 2006 | 5.1°C | 3.0°C | 0.8°C | 10.0°C | -3.1°C | 44 mm | 97% | 3.2 m/s | 0.5 |
| 2005 | 6.6°C | 4.2°C | 1.8°C | 10.8°C | -2.9°C | 92 mm | 94% | 5.6 m/s | 0.5 |
| 2004 | 5.1°C | 3.2°C | 1.3°C | 9.8°C | -3.0°C | 123 mm | 96% | 4 m/s | 0.5 |
| 2003 | 4.5°C | 2.5°C | 0.4°C | 10.8°C | -6.3°C | 81 mm | 95% | 4.7 m/s | 0.5 |
| 2002 | 5.8°C | 3.6°C | 1.4°C | 10.1°C | -6.4°C | 110 mm | 96% | 4.3 m/s | 0.5 |
| 2001 | 2.8°C | 1.1°C | -0.6°C | 5.2°C | -4.9°C | 50 mm | 97% | 2.9 m/s | 0.6 |
| 2000 | 5.5°C | 3.2°C | 0.9°C | 9.0°C | -2.1°C | 68 mm | 96% | 4.3 m/s | 0.6 |
| 1999 | 4.7°C | 3.0°C | 1.3°C | 8.3°C | -3.4°C | 113 mm | 96% | 4.6 m/s | 0.5 |
| 1998 | 4.6°C | 2.9°C | 1.2°C | 10.6°C | -3.1°C | 109 mm | 96% | 3.9 m/s | 0.6 |
| 1997 | 3.3°C | 1.3°C | -0.6°C | 9.4°C | -5.6°C | 35 mm | 97% | 2.5 m/s | 0.5 |
| 1996 | 4.0°C | 2.7°C | 1.4°C | 9.0°C | -3.9°C | 68 mm | 94% | 4.6 m/s | 0.4 |
| 1995 | 3.7°C | 1.4°C | -0.8°C | 9.2°C | -6.5°C | 101 mm | 95% | 4.9 m/s | 0.5 |
| 1994 | 3.9°C | 2.1°C | 0.4°C | 8.1°C | -2.9°C | 96 mm | 95% | 5 m/s | 0.4 |
| 1993 | 5.8°C | 3.3°C | 0.9°C | 10.9°C | -2.5°C | 145 mm | 93% | 6.8 m/s | 0.5 |
| 1992 | 4.8°C | 2.8°C | 0.9°C | 10.4°C | -6.0°C | 78 mm | 96% | 3.6 m/s | 0.5 |
| 1991 | 3.3°C | 1.1°C | -1.1°C | 9.6°C | -5.7°C | 86 mm | 96% | 4 m/s | 0.4 |
| 1990 | 6.0°C | 4.2°C | 2.4°C | 10.9°C | -1.7°C | 141 mm | 95% | 5.7 m/s | 0.5 |
| 1989 🔥 | 7.1°C | 5.3°C | 3.4°C | 9.9°C | 0.1°C | 86 mm | 95% | 5.7 m/s | 0.4 |
| 1988 | 4.1°C | 2.4°C | 0.7°C | 9.9°C | -2.4°C | 117 mm | 96% | 4 m/s | 0.5 |
| 1987 | 1.3°C | -0.6°C | -2.5°C | 6.0°C | -6.5°C | 50 mm | 95% | 3 m/s | 0.6 |
| 1986 | 2.6°C | 0.8°C | -1.0°C | 8.2°C | -7.1°C | 94 mm | 94% | 4.9 m/s | 0.5 |
| 1985 ❄️ | 0.7°C | -1.4°C | -3.6°C | 6.6°C | -13.6°C | 57 mm | 96% | 2.8 m/s | 0.6 |
| 1984 | 2.2°C | -0.2°C | -2.6°C | 8.9°C | -12.5°C | 136 mm | 94% | 4.8 m/s | 0.5 |
| 1983 | 6.0°C | 4.0°C | 2.1°C | 10.5°C | -3.2°C | 97 mm | 93% | 6.9 m/s | — |
| 1982 | 1.7°C | -0.8°C | -3.3°C | 8.9°C | -17.6°C | 122 mm | 97% | 3.6 m/s | — |
| 1981 | 4.9°C | 2.5°C | 0.2°C | 9.0°C | -4.2°C | 77 mm | 95% | 4.6 m/s | — |
Actual recorded January data for each year, 1981–2025 — sourced from NASA POWER.
The average high in January is around 4.4°C with lows near 0.3°C (mean 2.4°C), based on 45 years of NASA POWER data.
January averages 90 mm of rainfall in Hamilton, about average for rainfall. The wettest on record was 174 mm in 2016.
The hottest January reached 11.3°C in 2020. The coldest dipped to -17.6°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average January temperatures have risen by about 1.7°C. Daytime highs moved from 3.1°C to 4.5°C and overnight lows from -1.4°C to 0.5°C over the same span.
January is one of the cooler months of the year in Hamilton and about average for rainfall, so plan for around 4.4°C daytime highs and 0.3°C at night.
Yes — January is the coldest month of the year in Hamilton, averaging 2.4°C.
For January in Hamilton, pack warm layers and a jacket for chilly mornings, with typical highs of 4.4°C and lows of 0.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in January averages 95% — quite humid.
Average wind speed in January is 4.3 m/s. The windiest January on record averaged 6.9 m/s (1983).
The wettest January on record was 2016 with 174 mm. On average, January sees 90 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 Hamilton 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.
