December is one of the cooler months of the year in Santa Maria, with average highs near 15.9°C and lows around 8.9°C (mean 12.4°C). It is a relatively wet time of year, averaging 70 mm of rainfall and 72% relative humidity across the period.
December is one of the cooler months of the year in Santa Maria. Across 45 years of records, the warmest December in Santa Maria was 2017 — when the month averaged 15°C — while the coldest was 1998 at 10.6°C. Typical December days reach 15.9°C with nights near 8.9°C. The long-term trend is warming, about 0.2°C per decade.
December is a relatively wet time of year in Santa Maria, averaging 70 mm of rainfall. The wettest December on record was 2010 with 259 mm, while the driest was 1989 at 1 mm.
Relative humidity in Santa Maria during December averages 72%. The most humid December was 2019 at 83%, and the least humid was 2017 at 52%.
December receives about 2.7 kWh/m²/day of solar energy in Santa Maria. The sunniest Decembers were 1999, 2011 and 2013 at 3.1 kWh/m²/day, and the cloudiest was 2010 at 2.3.
Average wind speed in Santa Maria during December is 3.1 m/s. The windiest December was 1997 at 4 m/s, while the calmest were 1989 and 2000 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.3°C | 12.1°C | 12.1°C | 12.6°C | 13.3°C | +1°C |
| Avg High | 15.7°C | 15.8°C | 15.4°C | 16.1°C | 16.7°C | +1°C |
| Avg Low | 8.7°C | 8.4°C | 8.8°C | 9.2°C | 9.9°C | +1.2°C |
| Avg Rain | 57 mm | 60 mm | 68 mm | 75 mm | 104 mm | +47 mm |
December temperatures in Santa Maria have risen by about 1.2°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -0.7°C (1990) to a record high of 24.8°C (2017).
Rainfall in December is a relatively wet time of year, averaging 70 mm, with a wettest year of 259 mm.
A quieter season to visit Santa Maria
If your dates are flexible, the more temperate months of August and September tend to be the most comfortable for visiting Santa Maria. That said, December — with days averaging 15.9°C and nights around 8.9°C (mean 12.4°C) and moderate rainfall (70 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 | 18.3°C | 14.7°C | 11.2°C | 23.9°C | 8.1°C | 113 mm | 79% | 3.4 m/s | — |
| 2024 | 17.4°C | 13.7°C | 10.0°C | 22.2°C | 7.0°C | 16 mm | 77% | 2.7 m/s | 2.7 |
| 2023 | 17.6°C | 14.3°C | 11.1°C | 23.4°C | 8.1°C | 111 mm | 79% | 3 m/s | 2.6 |
| 2022 | 14.9°C | 12.0°C | 9.1°C | 20.3°C | 5.4°C | 186 mm | 80% | 3 m/s | 2.5 |
| 2021 | 14.6°C | 11.7°C | 8.8°C | 22.7°C | 6.4°C | 158 mm | 81% | 3.2 m/s | 2.4 |
| 2020 | 17.1°C | 13.2°C | 9.3°C | 23.2°C | 5.9°C | 40 mm | 66% | 2.9 m/s | 3 |
| 2019 | 15.4°C | 12.6°C | 9.9°C | 19.2°C | 5.9°C | 102 mm | 83% | 3.5 m/s | 2.5 |
| 2018 | 16.2°C | 12.7°C | 9.2°C | 20.3°C | 5.4°C | 29 mm | 76% | 3.4 m/s | 2.9 |
| 2017 🔥 | 19.6°C | 15.0°C | 10.4°C | 24.8°C | 5.4°C | 1 mm | 52% | 2.7 m/s | 3 |
| 2016 | 15.4°C | 12.0°C | 8.6°C | 19.6°C | 3.4°C | 87 mm | 74% | 3.1 m/s | 2.7 |
| 2015 | 15.3°C | 11.8°C | 8.3°C | 21.2°C | 3.4°C | 46 mm | 71% | 3.6 m/s | 2.8 |
| 2014 | 16.5°C | 13.7°C | 10.9°C | 21.5°C | 3.9°C | 118 mm | 81% | 3.6 m/s | 2.5 |
| 2013 | 16.9°C | 12.8°C | 8.7°C | 23.5°C | 2.4°C | 6 mm | 56% | 2.6 m/s | 3.1 |
| 2012 | 14.6°C | 11.6°C | 8.7°C | 18.9°C | 4.0°C | 92 mm | 77% | 3.1 m/s | 2.6 |
| 2011 | 16.0°C | 11.9°C | 7.7°C | 19.7°C | 5.4°C | 7 mm | 64% | 2.7 m/s | 3.1 |
| 2010 🌧️ | 14.8°C | 12.1°C | 9.3°C | 22.2°C | 4.3°C | 259 mm | 81% | 3.3 m/s | 2.3 |
| 2009 | 14.5°C | 11.4°C | 8.3°C | 19.2°C | 3.0°C | 76 mm | 74% | 3 m/s | 2.5 |
| 2008 | 14.9°C | 11.4°C | 7.9°C | 21.8°C | 4.2°C | 47 mm | 74% | 3.4 m/s | 2.8 |
| 2007 | 14.5°C | 10.9°C | 7.3°C | 21.4°C | 3.8°C | 57 mm | 73% | 3.6 m/s | 2.9 |
| 2006 | 16.4°C | 12.6°C | 8.8°C | 21.6°C | 4.4°C | 46 mm | 65% | 3.1 m/s | 2.9 |
| 2005 | 16.3°C | 13.1°C | 9.8°C | 20.5°C | 5.6°C | 59 mm | 75% | 2.6 m/s | 2.6 |
| 2004 | 16.2°C | 12.8°C | 9.4°C | 20.9°C | 5.1°C | 138 mm | 73% | 3.3 m/s | 2.7 |
| 2003 | 14.8°C | 11.8°C | 8.8°C | 18.5°C | 4.0°C | 61 mm | 78% | 3.1 m/s | 2.4 |
| 2002 | 14.6°C | 11.9°C | 9.2°C | 18.4°C | 5.1°C | 126 mm | 82% | 3 m/s | 2.6 |
| 2001 | 14.0°C | 11.2°C | 8.4°C | 20.8°C | 4.9°C | 63 mm | 82% | 3.3 m/s | 2.6 |
| 2000 | 17.5°C | 13.8°C | 10.1°C | 22.2°C | 7.3°C | 6 mm | 68% | 2.3 m/s | 2.8 |
| 1999 | 17.4°C | 13.2°C | 8.9°C | 21.8°C | 5.5°C | 3 mm | 60% | 3 m/s | 3.1 |
| 1998 ❄️ | 14.7°C | 10.6°C | 6.4°C | 23.6°C | 1.2°C | 18 mm | 69% | 3.4 m/s | 2.9 |
| 1997 | 15.6°C | 12.1°C | 8.7°C | 19.7°C | 4.6°C | 114 mm | 73% | 4 m/s | 2.8 |
| 1996 | 15.4°C | 12.5°C | 9.6°C | 19.5°C | 5.7°C | 137 mm | 81% | 3.4 m/s | 2.4 |
| 1995 | 16.6°C | 13.2°C | 9.8°C | 21.7°C | 5.8°C | 41 mm | 77% | 3.5 m/s | 2.5 |
| 1994 | 15.0°C | 11.5°C | 7.9°C | 19.6°C | 4.2°C | 29 mm | 75% | 2.9 m/s | 2.7 |
| 1993 | 16.4°C | 12.5°C | 8.6°C | 20.0°C | 6.0°C | 40 mm | 68% | 2.9 m/s | 2.9 |
| 1992 | 14.7°C | 11.4°C | 8.1°C | 19.4°C | 3.3°C | 106 mm | 74% | 3.4 m/s | 2.7 |
| 1991 | 16.5°C | 12.8°C | 9.2°C | 21.1°C | 5.7°C | 96 mm | 68% | 3 m/s | 2.7 |
| 1990 | 15.2°C | 11.1°C | 7.0°C | 22.2°C | -0.7°C | 14 mm | 57% | 3.2 m/s | 3 |
| 1989 | 18.6°C | 14.4°C | 10.2°C | 22.7°C | 7.2°C | 1 mm | 55% | 2.3 m/s | 3 |
| 1988 | 14.9°C | 11.6°C | 8.3°C | 21.5°C | 2.3°C | 111 mm | 68% | 3 m/s | 2.6 |
| 1987 | 13.9°C | 10.7°C | 7.4°C | 19.3°C | 2.1°C | 94 mm | 75% | 3.9 m/s | 2.5 |
| 1986 | 17.1°C | 13.4°C | 9.6°C | 21.1°C | 7.4°C | 25 mm | 68% | 2.5 m/s | 2.6 |
| 1985 | 16.4°C | 12.9°C | 9.4°C | 21.4°C | 3.8°C | 19 mm | 67% | 2.4 m/s | 2.7 |
| 1984 | 14.0°C | 10.7°C | 7.4°C | 18.3°C | 4.3°C | 84 mm | 77% | 3.8 m/s | 2.5 |
| 1983 | 15.1°C | 12.1°C | 9.0°C | 19.0°C | 5.5°C | 96 mm | 80% | 3.7 m/s | — |
| 1982 | 15.0°C | 11.5°C | 8.0°C | 19.1°C | 4.2°C | 52 mm | 73% | 3.6 m/s | — |
| 1981 | 16.7°C | 13.1°C | 9.4°C | 20.2°C | 5.8°C | 34 mm | 73% | 3.1 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 15.9°C with lows near 8.9°C (mean 12.4°C), based on 45 years of NASA POWER data.
December averages 70 mm of rainfall in Santa Maria, a relatively wet time of year. The wettest on record was 259 mm in 2010.
The hottest December reached 24.8°C in 2017. The coldest dipped to -0.7°C in 1990.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.2°C. Daytime highs moved from 15.4°C to 16.6°C and overnight lows from 8.6°C to 10°C over the same span.
December is one of the cooler months of the year in Santa Maria and a relatively wet time of year, so plan for around 15.9°C daytime highs and 8.9°C at night.
Not quite — December is the 3rd coolest month in Santa Maria, averaging 12.4°C.
For December in Santa Maria, pack light layers you can adjust through the day, with typical highs of 15.9°C and lows of 8.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 72% — moderately humid.
Average wind speed in December is 3.1 m/s. The windiest December on record averaged 4 m/s (1997).
The wettest December on record was 2010 with 259 mm. On average, December sees 70 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 Maria 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.
