December is one of the warmer months of the year in Westport, with average highs near 16.3°C and lows around 9°C (mean 12.7°C). It is a relatively wet time of year, averaging 178 mm of rainfall and 84% relative humidity across the period.
December is one of the warmer months of the year in Westport. Across 45 years of records, the warmest December in Westport was 2017 — when the month averaged 15.1°C — while the coldest was 2004 at 9.6°C. Typical December days reach 16.3°C with nights near 9°C. The long-term trend is warming, about 0.3°C per decade.
December is a relatively wet time of year in Westport, averaging 178 mm of rainfall. The wettest December on record was 1985 with 295 mm, while the driest was 2017 at 57 mm.
Relative humidity in Westport during December averages 84%. The most humid December was 2001 at 88%, and the least humid was 2017 at 80%.
December receives about 6.3 kWh/m²/day of solar energy in Westport. The sunniest December was 2017 at 7.6 kWh/m²/day, and the cloudiest was 2001 at 5.5.
Average wind speed in Westport during December is 0.4 m/s. The windiest Decembers were 2020, 2021 and 2025, among others at 0.4 m/s, while the calmest were 2022, 2023 and 2024, among others at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.6°C | 12.0°C | 12.2°C | 13.2°C | 13.4°C | +0.8°C |
| Avg High | 16.2°C | 15.7°C | 15.7°C | 17.0°C | 17.0°C | +0.8°C |
| Avg Low | 9.0°C | 8.3°C | 8.6°C | 9.4°C | 9.8°C | +0.8°C |
| Avg Rain | 208 mm | 167 mm | 172 mm | 173 mm | 172 mm | -36 mm |
December temperatures in Westport have risen by about 1°C between 1981–1985 and 2021–2025.
December has ranged from a record low of 1.7°C (1993) to a record high of 23.5°C (2012).
Rainfall in December is a relatively wet time of year, averaging 178 mm, with a wettest year of 295 mm.
One of the best times to visit Westport
December is one of the best times to visit Westport. Expect days averaging 16.3°C and nights around 9°C (mean 12.7°C) — warmer than Westport's yearly average — with higher rainfall (178 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 | 15.7°C | 12.2°C | 8.7°C | 19.4°C | 4.1°C | 153 mm | 84% | 0.4 m/s | — |
| 2024 | 18.1°C | 14.1°C | 10.0°C | 21.1°C | 4.8°C | 177 mm | 84% | 0.3 m/s | 6.5 |
| 2023 | 17.1°C | 13.7°C | 10.2°C | 21.8°C | 6.5°C | 220 mm | 86% | 0.3 m/s | 6 |
| 2022 | 18.0°C | 14.1°C | 10.3°C | 22.6°C | 7.0°C | 83 mm | 83% | 0.3 m/s | 7.3 |
| 2021 | 16.9°C | 13.8°C | 10.7°C | 19.8°C | 6.2°C | 210 mm | 87% | 0.4 m/s | 5.6 |
| 2020 | 16.2°C | 12.5°C | 8.7°C | 20.7°C | 2.9°C | 190 mm | 84% | 0.4 m/s | 6.5 |
| 2019 | 15.6°C | 12.1°C | 8.7°C | 20.2°C | 4.2°C | 204 mm | 85% | 0.4 m/s | 6.1 |
| 2018 | 18.4°C | 14.3°C | 10.3°C | 21.6°C | 4.9°C | 96 mm | 84% | 0.3 m/s | 6.6 |
| 2017 🔥 | 19.4°C | 15.1°C | 10.8°C | 22.9°C | 5.6°C | 57 mm | 80% | 0.3 m/s | 7.6 |
| 2016 | 15.5°C | 11.8°C | 8.0°C | 18.9°C | 5.4°C | 180 mm | 85% | 0.4 m/s | 6.2 |
| 2015 | 15.8°C | 12.0°C | 8.2°C | 21.6°C | 4.1°C | 135 mm | 84% | 0.3 m/s | 6.4 |
| 2014 | 17.1°C | 13.4°C | 9.7°C | 22.3°C | 2.3°C | 231 mm | 85% | 0.3 m/s | 6.1 |
| 2013 | 16.6°C | 12.8°C | 9.1°C | 21.6°C | 5.4°C | 159 mm | 84% | 0.3 m/s | 6.3 |
| 2012 | 17.1°C | 13.1°C | 9.2°C | 23.5°C | 4.7°C | 152 mm | 85% | 0.3 m/s | 6.4 |
| 2011 | 17.6°C | 13.7°C | 9.7°C | 20.9°C | 6.9°C | 267 mm | 84% | 0.3 m/s | 6 |
| 2010 | 17.1°C | 13.8°C | 10.4°C | 21.0°C | 7.8°C | 247 mm | 84% | 0.3 m/s | 6 |
| 2009 | 15.3°C | 11.8°C | 8.2°C | 18.5°C | 3.6°C | 222 mm | 85% | 0.4 m/s | 5.9 |
| 2008 | 16.0°C | 12.4°C | 8.8°C | 21.8°C | 4.0°C | 130 mm | 84% | 0.4 m/s | 6.2 |
| 2007 | 16.8°C | 13.2°C | 9.6°C | 20.7°C | 4.5°C | 149 mm | 85% | 0.3 m/s | 6.2 |
| 2006 | 14.3°C | 10.2°C | 6.1°C | 17.7°C | 2.0°C | 152 mm | 81% | 0.3 m/s | 6.8 |
| 2005 | 17.5°C | 13.9°C | 10.2°C | 22.2°C | 5.3°C | 181 mm | 86% | 0.3 m/s | 6 |
| 2004 ❄️ | 12.9°C | 9.6°C | 6.3°C | 17.3°C | 2.5°C | 214 mm | 85% | 0.4 m/s | 6.1 |
| 2003 | 16.0°C | 12.3°C | 8.7°C | 20.4°C | 5.1°C | 157 mm | 85% | 0.4 m/s | 6.3 |
| 2002 | 15.4°C | 12.2°C | 9.0°C | 20.2°C | 4.4°C | 150 mm | 85% | 0.4 m/s | 6.3 |
| 2001 | 16.2°C | 13.2°C | 10.1°C | 19.7°C | 4.8°C | 242 mm | 88% | 0.4 m/s | 5.5 |
| 2000 | 16.5°C | 12.8°C | 9.1°C | 20.7°C | 5.7°C | 120 mm | 84% | 0.4 m/s | 6.6 |
| 1999 | 15.7°C | 11.9°C | 8.1°C | 18.9°C | 3.7°C | 67 mm | 81% | 0.4 m/s | 6.9 |
| 1998 | 16.3°C | 12.9°C | 9.5°C | 21.0°C | 5.3°C | 180 mm | 85% | 0.3 m/s | 6.3 |
| 1997 | 14.6°C | 10.9°C | 7.2°C | 18.4°C | 2.1°C | 178 mm | 83% | 0.3 m/s | 6.2 |
| 1996 | 15.6°C | 11.5°C | 7.5°C | 21.6°C | 2.2°C | 114 mm | 83% | 0.4 m/s | 6.7 |
| 1995 | 16.3°C | 13.2°C | 10.0°C | 20.4°C | 4.5°C | 266 mm | 86% | 0.4 m/s | 6 |
| 1994 | 16.2°C | 12.3°C | 8.3°C | 19.8°C | 4.6°C | 91 mm | 81% | 0.3 m/s | 6.7 |
| 1993 | 15.0°C | 11.3°C | 7.6°C | 19.5°C | 1.7°C | 157 mm | 84% | 0.3 m/s | 6 |
| 1992 | 15.8°C | 12.0°C | 8.3°C | 19.5°C | 2.3°C | 200 mm | 82% | 0.4 m/s | 5.9 |
| 1991 | 15.7°C | 11.9°C | 8.1°C | 19.7°C | 3.2°C | 202 mm | 85% | 0.3 m/s | 6 |
| 1990 | 15.5°C | 12.0°C | 8.6°C | 19.0°C | 5.3°C | 216 mm | 84% | 0.4 m/s | 6.6 |
| 1989 | 15.4°C | 11.8°C | 8.2°C | 18.3°C | 4.0°C | 266 mm | 84% | 0.4 m/s | 6.7 |
| 1988 | 17.7°C | 13.7°C | 9.7°C | 22.1°C | 5.6°C | 62 mm | 82% | 0.4 m/s | 7.1 |
| 1987 | 15.6°C | 12.0°C | 8.4°C | 21.6°C | 5.4°C | 251 mm | 85% | 0.4 m/s | 5.8 |
| 1986 | 17.1°C | 13.1°C | 9.1°C | 20.9°C | 2.3°C | 156 mm | 82% | 0.4 m/s | 6.6 |
| 1985 🌧️ | 16.8°C | 13.3°C | 9.9°C | 19.7°C | 5.2°C | 295 mm | 86% | 0.4 m/s | 6.1 |
| 1984 | 17.3°C | 13.4°C | 9.5°C | 22.3°C | 5.4°C | 229 mm | 83% | 0.4 m/s | 6.2 |
| 1983 | 14.6°C | 11.3°C | 7.9°C | 18.9°C | 4.4°C | 269 mm | 86% | 0.4 m/s | — |
| 1982 | 14.1°C | 10.6°C | 7.2°C | 19.2°C | 2.5°C | 168 mm | 85% | 0.4 m/s | — |
| 1981 | 17.4°C | 14.2°C | 10.9°C | 21.6°C | 7.1°C | 177 mm | 86% | 0.4 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 16.3°C with lows near 9°C (mean 12.7°C), based on 45 years of NASA POWER data.
December averages 178 mm of rainfall in Westport, a relatively wet time of year. The wettest on record was 295 mm in 1985.
The hottest December reached 23.5°C in 2012. The coldest dipped to 1.7°C in 1993.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1°C. Daytime highs moved from 16°C to 17.2°C and overnight lows from 9.1°C to 10°C over the same span.
December is one of the warmer months of the year in Westport and a relatively wet time of year, so plan for around 16.3°C daytime highs and 9°C at night.
Not quite — December is the 9th coolest month in Westport, averaging 12.7°C.
For December in Westport, pack light layers you can adjust through the day, with typical highs of 16.3°C and lows of 9°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 84% — quite humid.
Average wind speed in December is 0.4 m/s. The windiest December on record averaged 0.4 m/s (1981).
The wettest December on record was 1985 with 295 mm. On average, December sees 178 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 Westport 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.
