December is one of the cooler months of the year in Santa Clara, with average highs near 14°C and lows around 4.1°C (mean 9.1°C). It is a relatively wet time of year, averaging 106 mm of rainfall and 81% relative humidity across the period.
December is one of the cooler months of the year in Santa Clara. Across 45 years of records, the warmest December in Santa Clara was 2023 — when the month averaged 11.5°C — while the coldest was 1998 at 7°C. Typical December days reach 14°C with nights near 4.1°C. The long-term trend is warming, about 0.2°C per decade.
December is a relatively wet time of year in Santa Clara, averaging 106 mm of rainfall. The wettest December on record was 2022 with 295 mm, while the driest was 2011 at 3 mm.
Relative humidity in Santa Clara during December averages 81%. The most humid December was 1983 at 91%, and the least humid was 2013 at 64%.
December receives about 2.2 kWh/m²/day of solar energy in Santa Clara. The sunniest December was 2013 at 2.8 kWh/m²/day, and the cloudiest were 2002, 2003 and 2010, among others at 1.8.
Average wind speed in Santa Clara during December is 1.8 m/s. The windiest December was 1987 at 2.6 m/s, while the calmest were 1986 and 1989 at 1.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.9°C | 8.7°C | 9.0°C | 9.1°C | 10.0°C | +1.1°C |
| Avg High | 13.9°C | 14.0°C | 13.7°C | 14.0°C | 14.8°C | +0.9°C |
| Avg Low | 3.8°C | 3.4°C | 4.2°C | 4.3°C | 5.1°C | +1.3°C |
| Avg Rain | 81 mm | 90 mm | 122 mm | 103 mm | 146 mm | +66 mm |
December temperatures in Santa Clara have risen by about 1.5°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -6.6°C (1990) to a record high of 23.5°C (1990).
Rainfall in December is a relatively wet time of year, averaging 106 mm, with a wettest year of 295 mm.
A quieter season to visit Santa Clara
If your dates are flexible, the more temperate months of August and July tend to be the most comfortable for visiting Santa Clara. That said, December — with days averaging 14°C and nights around 4.1°C (mean 9.1°C) and higher rainfall (106 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 | 14.8°C | 10.1°C | 5.4°C | 18.5°C | 0.9°C | 95 mm | 87% | 1.8 m/s | — |
| 2024 | 16.1°C | 11.1°C | 6.2°C | 21.5°C | 1.0°C | 119 mm | 85% | 1.7 m/s | 2.1 |
| 2023 🔥 | 16.5°C | 11.5°C | 6.5°C | 22.1°C | 1.5°C | 110 mm | 84% | 1.5 m/s | 2.2 |
| 2022 🌧️ | 12.9°C | 8.6°C | 4.3°C | 16.6°C | -0.7°C | 295 mm | 89% | 1.7 m/s | 1.9 |
| 2021 | 12.7°C | 8.6°C | 4.4°C | 23.4°C | -0.8°C | 216 mm | 89% | 1.9 m/s | 1.9 |
| 2020 | 15.9°C | 10.0°C | 4.1°C | 21.0°C | -2.2°C | 43 mm | 77% | 1.6 m/s | 2.5 |
| 2019 | 14.0°C | 10.0°C | 6.0°C | 17.8°C | 0.8°C | 138 mm | 89% | 1.8 m/s | 1.9 |
| 2018 | 14.4°C | 9.6°C | 4.9°C | 17.8°C | 0.0°C | 59 mm | 83% | 1.6 m/s | 2.3 |
| 2017 | 15.9°C | 9.5°C | 3.2°C | 19.5°C | -1.2°C | 3 mm | 65% | 1.5 m/s | 2.7 |
| 2016 | 12.5°C | 7.9°C | 3.2°C | 17.0°C | -3.2°C | 103 mm | 87% | 1.8 m/s | 2.3 |
| 2015 | 13.0°C | 8.4°C | 3.9°C | 18.1°C | -2.9°C | 110 mm | 83% | 1.8 m/s | 2.2 |
| 2014 | 14.7°C | 10.7°C | 6.7°C | 19.9°C | -2.1°C | 255 mm | 90% | 1.9 m/s | 1.9 |
| 2013 | 14.9°C | 8.5°C | 2.1°C | 20.3°C | -4.8°C | 16 mm | 64% | 1.5 m/s | 2.8 |
| 2012 | 12.4°C | 8.4°C | 4.4°C | 17.3°C | -1.4°C | 174 mm | 86% | 1.9 m/s | 2 |
| 2011 | 14.7°C | 8.6°C | 2.5°C | 20.1°C | -2.4°C | 3 mm | 67% | 1.5 m/s | 2.6 |
| 2010 | 13.7°C | 9.7°C | 5.7°C | 18.4°C | -0.3°C | 170 mm | 88% | 1.8 m/s | 1.8 |
| 2009 | 12.3°C | 7.7°C | 3.0°C | 17.6°C | -3.3°C | 81 mm | 84% | 1.6 m/s | 2.1 |
| 2008 | 12.5°C | 7.5°C | 2.5°C | 18.6°C | -3.4°C | 65 mm | 82% | 1.7 m/s | 2.2 |
| 2007 | 12.5°C | 7.5°C | 2.5°C | 19.0°C | -2.4°C | 68 mm | 78% | 1.9 m/s | 2.4 |
| 2006 | 14.5°C | 8.9°C | 3.3°C | 20.3°C | -3.6°C | 73 mm | 73% | 1.9 m/s | 2.3 |
| 2005 | 14.7°C | 10.3°C | 6.0°C | 20.3°C | -1.9°C | 201 mm | 83% | 2 m/s | 1.9 |
| 2004 | 14.7°C | 9.5°C | 4.3°C | 18.6°C | -1.9°C | 138 mm | 81% | 1.9 m/s | 2.2 |
| 2003 | 13.5°C | 9.4°C | 5.4°C | 18.3°C | 0.3°C | 161 mm | 84% | 1.9 m/s | 1.8 |
| 2002 | 14.1°C | 10.2°C | 6.2°C | 19.6°C | -0.5°C | 240 mm | 86% | 2.3 m/s | 1.8 |
| 2001 | 12.5°C | 8.8°C | 5.1°C | 17.0°C | 0.8°C | 182 mm | 88% | 2.1 m/s | 1.8 |
| 2000 | 15.5°C | 9.8°C | 4.1°C | 19.4°C | -0.3°C | 15 mm | 75% | 1.4 m/s | 2.2 |
| 1999 | 16.2°C | 9.8°C | 3.4°C | 20.0°C | -0.3°C | 8 mm | 72% | 1.6 m/s | 2.7 |
| 1998 ❄️ | 12.3°C | 7.0°C | 1.6°C | 21.3°C | -6.0°C | 31 mm | 80% | 1.6 m/s | 2.5 |
| 1997 | 13.2°C | 8.0°C | 2.8°C | 17.2°C | -2.4°C | 74 mm | 81% | 2 m/s | 2.3 |
| 1996 | 14.3°C | 10.2°C | 6.2°C | 18.0°C | 1.9°C | 215 mm | 87% | 2.4 m/s | 2 |
| 1995 | 15.5°C | 10.9°C | 6.2°C | 22.0°C | 0.0°C | 166 mm | 85% | 1.9 m/s | 2 |
| 1994 | 12.4°C | 7.7°C | 2.9°C | 18.2°C | -4.2°C | 64 mm | 84% | 1.6 m/s | 2.1 |
| 1993 | 14.5°C | 8.9°C | 3.3°C | 19.1°C | -2.8°C | 61 mm | 79% | 1.7 m/s | 2.2 |
| 1992 | 12.9°C | 7.9°C | 2.8°C | 18.3°C | -2.2°C | 165 mm | 82% | 2.2 m/s | 2.3 |
| 1991 | 15.7°C | 9.6°C | 3.5°C | 19.7°C | -2.1°C | 67 mm | 71% | 1.7 m/s | 2.4 |
| 1990 | 13.3°C | 7.3°C | 1.3°C | 23.5°C | -6.6°C | 44 mm | 64% | 1.7 m/s | 2.6 |
| 1989 | 16.9°C | 10.3°C | 3.7°C | 20.8°C | -1.1°C | 5 mm | 67% | 1.3 m/s | 2.7 |
| 1988 | 14.2°C | 8.9°C | 3.5°C | 23.4°C | -2.9°C | 96 mm | 74% | 1.8 m/s | 2.3 |
| 1987 | 12.6°C | 8.0°C | 3.5°C | 18.7°C | -3.6°C | 110 mm | 79% | 2.6 m/s | 2.2 |
| 1986 | 16.0°C | 10.1°C | 4.1°C | 23.3°C | 0.5°C | 37 mm | 71% | 1.3 m/s | 2.2 |
| 1985 | 13.8°C | 8.0°C | 2.3°C | 18.3°C | -4.2°C | 62 mm | 81% | 1.5 m/s | 2.2 |
| 1984 | 12.2°C | 7.4°C | 2.6°C | 18.2°C | -0.9°C | 50 mm | 86% | 1.7 m/s | 2.2 |
| 1983 | 12.8°C | 9.4°C | 6.0°C | 17.0°C | 0.3°C | 160 mm | 91% | 2.1 m/s | — |
| 1982 | 12.8°C | 7.9°C | 3.0°C | 16.6°C | -3.0°C | 91 mm | 83% | 2 m/s | — |
| 1981 | 14.1°C | 9.8°C | 5.5°C | 19.9°C | 1.7°C | 114 mm | 87% | 1.8 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 14°C with lows near 4.1°C (mean 9.1°C), based on 45 years of NASA POWER data.
December averages 106 mm of rainfall in Santa Clara, a relatively wet time of year. The wettest on record was 295 mm in 2022.
The hottest December reached 23.5°C in 1990. The coldest dipped to -6.6°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.5°C. Daytime highs moved from 13.1°C to 14.6°C and overnight lows from 3.9°C to 5.4°C over the same span.
December is one of the cooler months of the year in Santa Clara and a relatively wet time of year, so plan for around 14°C daytime highs and 4.1°C at night.
Yes — December is the coldest month of the year in Santa Clara, averaging 9.1°C.
For December in Santa Clara, pack warm layers and a jacket for chilly mornings, with typical highs of 14°C and lows of 4.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 81% — quite humid.
Average wind speed in December is 1.8 m/s. The windiest December on record averaged 2.6 m/s (1987).
The wettest December on record was 2022 with 295 mm. On average, December sees 106 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 Santa Clara 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.
