December is one of the cooler months of the year in Nelson, with average highs near -6.8°C and lows around -14.4°C (mean -10.6°C). It is a relatively wet time of year, averaging 83 mm of rainfall and 98% relative humidity across the period.
December is one of the cooler months of the year in Nelson. Across 45 years of records, the warmest December in Nelson was 2025 — when the month averaged -6°C — while the coldest was 1983 at -16.9°C. Typical December days reach -6.8°C with nights near -14.4°C. The long-term trend is warming, about 0.7°C per decade.
December is a relatively wet time of year in Nelson, averaging 83 mm of rainfall. The wettest December on record was 2025 with 212 mm, while the driest was 1985 at 24 mm.
Relative humidity in Nelson during December averages 98%. The most humid December was 1985 at 100%, and the least humid was 2003 at 97%.
December receives about 0.8 kWh/m²/day of solar energy in Nelson. The sunniest Decembers were 2009, 2011 and 2017, among others at 0.9 kWh/m²/day, and the cloudiest were 1998, 2012 and 2019 at 0.6.
Average wind speed in Nelson during December is 0.5 m/s. The windiest Decembers were 2009, 2010 and 2016, among others at 0.6 m/s, while the calmest were 2002, 2021 and 2025 at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | -12.1°C | -10.9°C | -10.3°C | -10.6°C | -8.7°C | +3.4°C |
| Avg High | -8.0°C | -7.1°C | -6.4°C | -6.8°C | -5.2°C | +2.8°C |
| Avg Low | -16.1°C | -14.7°C | -14.1°C | -14.3°C | -12.1°C | +4°C |
| Avg Rain | 60 mm | 83 mm | 71 mm | 94 mm | 119 mm | +59 mm |
December temperatures in Nelson have risen by about 4.5°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -40.8°C (1990) to a record high of 2.6°C (2021).
Rainfall in December is a relatively wet time of year, averaging 83 mm, with a wettest year of 212 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.6°C per decade while lows rose 0.8°C per decade, narrowing the gap between day and night.
A quieter season to visit Nelson
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Nelson. That said, December — with days averaging -6.8°C and nights around -14.4°C (mean -10.6°C) and higher rainfall (83 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 🔥 🌧️ | -2.9°C | -6.0°C | -9.1°C | 0.4°C | -24.8°C | 212 mm | 99% | 0.4 m/s | — |
| 2024 | -3.9°C | -7.1°C | -10.2°C | 0.1°C | -17.8°C | 131 mm | 99% | 0.5 m/s | 0.7 |
| 2023 | -2.8°C | -6.1°C | -9.3°C | 1.3°C | -19.1°C | 113 mm | 98% | 0.5 m/s | 0.7 |
| 2022 | -9.1°C | -13.2°C | -17.2°C | 0.0°C | -33.3°C | 84 mm | 98% | 0.5 m/s | 0.8 |
| 2021 | -8.1°C | -11.9°C | -15.6°C | 2.6°C | -32.6°C | 88 mm | 97% | 0.4 m/s | 0.8 |
| 2020 | -4.5°C | -8.0°C | -11.5°C | 0.1°C | -20.2°C | 83 mm | 98% | 0.5 m/s | 0.8 |
| 2019 | -4.8°C | -8.3°C | -11.8°C | 0.0°C | -19.0°C | 122 mm | 99% | 0.5 m/s | 0.6 |
| 2018 | -5.8°C | -9.5°C | -13.1°C | 0.0°C | -23.1°C | 105 mm | 99% | 0.5 m/s | 0.7 |
| 2017 | -8.9°C | -12.9°C | -16.8°C | -1.0°C | -27.2°C | 82 mm | 98% | 0.5 m/s | 0.9 |
| 2016 | -10.6°C | -14.9°C | -19.2°C | -2.6°C | -32.5°C | 87 mm | 99% | 0.6 m/s | 0.8 |
| 2015 | -6.1°C | -9.7°C | -13.3°C | 0.5°C | -23.2°C | 132 mm | 99% | 0.5 m/s | 0.7 |
| 2014 | -5.1°C | -8.7°C | -12.2°C | 1.0°C | -27.9°C | 103 mm | 99% | 0.5 m/s | 0.8 |
| 2013 | -8.1°C | -12.1°C | -16.1°C | -0.2°C | -36.4°C | 74 mm | 99% | 0.5 m/s | 0.8 |
| 2012 | -6.0°C | -9.2°C | -12.4°C | 0.0°C | -21.5°C | 118 mm | 99% | 0.5 m/s | 0.6 |
| 2011 | -6.6°C | -10.5°C | -14.3°C | 0.1°C | -20.3°C | 43 mm | 100% | 0.5 m/s | 0.9 |
| 2010 | -5.7°C | -9.9°C | -14.2°C | 0.0°C | -28.5°C | 70 mm | 97% | 0.6 m/s | 0.8 |
| 2009 | -9.8°C | -14.1°C | -18.5°C | -0.1°C | -33.3°C | 52 mm | 97% | 0.6 m/s | 0.9 |
| 2008 | -9.6°C | -13.8°C | -18.0°C | 0.9°C | -34.8°C | 71 mm | 97% | 0.5 m/s | 0.8 |
| 2007 | -6.7°C | -10.3°C | -14.0°C | 0.1°C | -25.1°C | 105 mm | 99% | 0.5 m/s | 0.7 |
| 2006 | -5.5°C | -9.2°C | -12.8°C | 0.0°C | -21.4°C | 75 mm | 98% | 0.5 m/s | 0.7 |
| 2005 | -6.7°C | -10.4°C | -14.2°C | 1.3°C | -25.9°C | 56 mm | 99% | 0.5 m/s | 0.8 |
| 2004 | -4.5°C | -8.3°C | -12.2°C | 0.1°C | -22.5°C | 83 mm | 99% | 0.5 m/s | 0.7 |
| 2003 | -5.7°C | -9.6°C | -13.5°C | 0.0°C | -24.5°C | 58 mm | 97% | 0.6 m/s | 0.8 |
| 2002 | -3.1°C | -6.4°C | -9.8°C | 0.8°C | -18.7°C | 86 mm | 97% | 0.4 m/s | 0.7 |
| 2001 | -5.9°C | -9.9°C | -13.9°C | -0.4°C | -19.9°C | 96 mm | 98% | 0.5 m/s | 0.8 |
| 2000 | -6.8°C | -10.7°C | -14.5°C | 0.0°C | -24.8°C | 31 mm | 97% | 0.5 m/s | 0.8 |
| 1999 | -4.7°C | -8.2°C | -11.7°C | 0.0°C | -19.0°C | 69 mm | 99% | 0.5 m/s | 0.7 |
| 1998 | -7.6°C | -11.0°C | -14.4°C | 0.1°C | -36.1°C | 128 mm | 99% | 0.5 m/s | 0.6 |
| 1997 | -4.2°C | -8.0°C | -11.8°C | 0.6°C | -20.8°C | 43 mm | 98% | 0.5 m/s | 0.8 |
| 1996 | -9.8°C | -13.8°C | -17.8°C | 0.1°C | -31.3°C | 119 mm | 99% | 0.5 m/s | 0.7 |
| 1995 | -6.7°C | -10.9°C | -15.0°C | 0.1°C | -36.2°C | 92 mm | 98% | 0.5 m/s | 0.8 |
| 1994 | -6.5°C | -10.5°C | -14.5°C | 0.0°C | -31.9°C | 87 mm | 99% | 0.5 m/s | 0.9 |
| 1993 | -5.9°C | -9.5°C | -13.2°C | 0.0°C | -20.4°C | 97 mm | 99% | 0.5 m/s | 0.7 |
| 1992 | -9.4°C | -13.5°C | -17.5°C | -1.3°C | -27.4°C | 57 mm | 98% | 0.5 m/s | 0.8 |
| 1991 | -4.2°C | -7.8°C | -11.3°C | -0.1°C | -19.5°C | 47 mm | 98% | 0.5 m/s | 0.8 |
| 1990 | -11.7°C | -16.0°C | -20.2°C | 0.0°C | -40.8°C | 89 mm | 99% | 0.5 m/s | 0.7 |
| 1989 | -5.4°C | -9.0°C | -12.5°C | 0.3°C | -23.8°C | 49 mm | 99% | 0.5 m/s | 0.7 |
| 1988 | -6.9°C | -11.2°C | -15.4°C | -0.7°C | -29.6°C | 48 mm | 99% | 0.5 m/s | 0.8 |
| 1987 | -7.0°C | -10.8°C | -14.5°C | 0.1°C | -25.2°C | 95 mm | 97% | 0.5 m/s | 0.7 |
| 1986 | -6.8°C | -10.5°C | -14.3°C | -2.0°C | -22.5°C | 37 mm | 99% | 0.5 m/s | 0.8 |
| 1985 | -7.7°C | -11.6°C | -15.6°C | -1.1°C | -33.0°C | 24 mm | 100% | 0.5 m/s | 0.8 |
| 1984 | -11.7°C | -16.2°C | -20.7°C | -4.2°C | -35.3°C | 58 mm | 98% | 0.5 m/s | 0.9 |
| 1983 ❄️ | -12.3°C | -16.9°C | -21.5°C | -3.6°C | -40.5°C | 44 mm | 99% | 0.6 m/s | — |
| 1982 | -7.5°C | -11.4°C | -15.2°C | 0.1°C | -25.2°C | 100 mm | 100% | 0.5 m/s | — |
| 1981 | -7.1°C | -11.1°C | -15.2°C | 0.1°C | -25.9°C | 81 mm | 99% | 0.5 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around -6.8°C with lows near -14.4°C (mean -10.6°C), based on 45 years of NASA POWER data.
December averages 83 mm of rainfall in Nelson, a relatively wet time of year. The wettest on record was 212 mm in 2025.
The hottest December reached 2.6°C in 2021. The coldest dipped to -40.8°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 4.5°C. Daytime highs moved from -9.3°C to -5.4°C and overnight lows from -17.6°C to -12.3°C over the same span.
December is one of the cooler months of the year in Nelson and a relatively wet time of year, so plan for around -6.8°C daytime highs and -14.4°C at night.
Yes — December is the coldest month of the year in Nelson, averaging -10.6°C.
For December in Nelson, pack warm layers and a jacket for chilly mornings, with typical highs of -6.8°C and lows of -14.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 98% — quite humid.
Average wind speed in December is 0.5 m/s. The windiest December on record averaged 0.6 m/s (1983).
The wettest December on record was 2025 with 212 mm. On average, December sees 83 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 Nelson behaves each December, 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 December specifically, along with year-by-year records and how the month has changed over the decades.
