December is one of the cooler months of the year in Modesto, with average highs near 14°C and lows around 4°C (mean 9°C). It is a relatively wet time of year, averaging 84 mm of rainfall and 77% relative humidity across the period.
December is one of the cooler months of the year in Modesto. Across 45 years of records, the warmest December in Modesto was 2023 — when the month averaged 11.6°C — while the coldest was 1998 at 7°C. Typical December days reach 14°C with nights near 4°C. The long-term trend is warming, about 0.2°C per decade.
December is a relatively wet time of year in Modesto, averaging 84 mm of rainfall. The wettest December on record was 2022 with 237 mm, while the driest was 2017 at 3 mm.
Relative humidity in Modesto during December averages 77%. The most humid December was 1983 at 89%, and the least humid was 2013 at 58%.
December receives about 2.1 kWh/m²/day of solar energy in Modesto. The sunniest December was 2013 at 2.8 kWh/m²/day, and the cloudiest were 1996 and 2010 at 1.7.
Average wind speed in Modesto during December is 1.8 m/s. The windiest December was 1987 at 2.8 m/s, while the calmest was 1989 at 1.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.9°C | 8.8°C | 8.9°C | 9.1°C | 9.9°C | +1°C |
| Avg High | 14.0°C | 14.2°C | 13.6°C | 14.0°C | 14.7°C | +0.7°C |
| Avg Low | 3.8°C | 3.4°C | 4.2°C | 4.2°C | 5.1°C | +1.3°C |
| Avg Rain | 63 mm | 73 mm | 102 mm | 83 mm | 108 mm | +46 mm |
December temperatures in Modesto have risen by about 1.3°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -6.6°C (1990) to a record high of 24°C (1986).
Rainfall in December is a relatively wet time of year, averaging 84 mm, with a wettest year of 237 mm.
A quieter season to visit Modesto
If your dates are flexible, the more temperate months of June and September tend to be the most comfortable for visiting Modesto. That said, December — with days averaging 14°C and nights around 4°C (mean 9°C) and higher rainfall (84 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 | 14.2°C | 9.8°C | 5.3°C | 20.1°C | 1.2°C | 66 mm | 86% | 1.5 m/s | — |
| 2024 | 16.5°C | 11.5°C | 6.4°C | 21.3°C | 1.2°C | 77 mm | 80% | 1.6 m/s | 2.1 |
| 2023 🔥 | 16.6°C | 11.6°C | 6.5°C | 21.0°C | 1.3°C | 75 mm | 80% | 1.5 m/s | 2.3 |
| 2022 🌧️ | 12.4°C | 8.3°C | 4.2°C | 15.7°C | -0.2°C | 237 mm | 87% | 1.6 m/s | 1.9 |
| 2021 | 12.6°C | 8.4°C | 4.1°C | 23.3°C | 0.2°C | 160 mm | 87% | 1.9 m/s | 1.8 |
| 2020 | 15.9°C | 10.0°C | 4.0°C | 21.9°C | 0.0°C | 34 mm | 71% | 1.6 m/s | 2.3 |
| 2019 | 14.0°C | 9.8°C | 5.6°C | 18.3°C | -0.2°C | 116 mm | 85% | 2 m/s | 2 |
| 2018 | 14.2°C | 9.4°C | 4.6°C | 17.6°C | 0.2°C | 53 mm | 80% | 1.7 m/s | 2.2 |
| 2017 | 15.6°C | 9.7°C | 3.7°C | 19.0°C | -0.8°C | 3 mm | 59% | 1.4 m/s | 2.7 |
| 2016 | 12.7°C | 7.9°C | 3.2°C | 18.7°C | -3.2°C | 74 mm | 84% | 1.8 m/s | 2.3 |
| 2015 | 13.0°C | 8.2°C | 3.3°C | 19.5°C | -3.7°C | 78 mm | 79% | 1.9 m/s | 2.2 |
| 2014 | 14.8°C | 10.7°C | 6.6°C | 21.4°C | -2.2°C | 200 mm | 87% | 2.1 m/s | 1.9 |
| 2013 | 14.8°C | 8.6°C | 2.5°C | 20.6°C | -4.2°C | 13 mm | 58% | 1.4 m/s | 2.8 |
| 2012 | 12.4°C | 8.1°C | 3.8°C | 18.4°C | -2.5°C | 144 mm | 85% | 2 m/s | 1.9 |
| 2011 | 14.6°C | 8.6°C | 2.7°C | 19.0°C | -2.0°C | 3 mm | 61% | 1.5 m/s | 2.7 |
| 2010 | 13.7°C | 9.7°C | 5.7°C | 18.7°C | -1.8°C | 144 mm | 85% | 1.8 m/s | 1.7 |
| 2009 | 12.3°C | 7.6°C | 3.0°C | 18.7°C | -3.2°C | 71 mm | 79% | 1.6 m/s | 2.1 |
| 2008 | 12.2°C | 7.3°C | 2.3°C | 19.0°C | -2.4°C | 52 mm | 79% | 1.8 m/s | 2.1 |
| 2007 | 12.3°C | 7.2°C | 2.1°C | 19.3°C | -2.7°C | 58 mm | 75% | 2.1 m/s | 2.3 |
| 2006 | 14.1°C | 8.8°C | 3.4°C | 20.2°C | -3.5°C | 65 mm | 68% | 1.9 m/s | 2.2 |
| 2005 | 14.8°C | 10.5°C | 6.2°C | 21.4°C | -1.7°C | 172 mm | 79% | 1.9 m/s | 1.8 |
| 2004 | 14.9°C | 9.8°C | 4.7°C | 20.3°C | -0.9°C | 119 mm | 76% | 1.9 m/s | 2 |
| 2003 | 13.6°C | 9.5°C | 5.4°C | 18.8°C | 0.5°C | 131 mm | 79% | 2 m/s | 1.8 |
| 2002 | 13.8°C | 9.7°C | 5.6°C | 19.0°C | -1.3°C | 193 mm | 83% | 2.2 m/s | 1.8 |
| 2001 | 12.7°C | 8.7°C | 4.7°C | 19.4°C | -0.5°C | 150 mm | 84% | 2.2 m/s | 1.9 |
| 2000 | 15.6°C | 10.0°C | 4.4°C | 19.1°C | 1.1°C | 12 mm | 70% | 1.3 m/s | 2.2 |
| 1999 | 16.4°C | 10.0°C | 3.7°C | 20.4°C | -0.5°C | 6 mm | 66% | 1.8 m/s | 2.6 |
| 1998 ❄️ | 12.5°C | 7.0°C | 1.5°C | 23.0°C | -5.8°C | 25 mm | 76% | 1.8 m/s | 2.4 |
| 1997 | 13.2°C | 7.9°C | 2.7°C | 18.3°C | -2.3°C | 63 mm | 76% | 2 m/s | 2.1 |
| 1996 | 14.5°C | 10.1°C | 5.8°C | 17.8°C | -0.1°C | 182 mm | 84% | 2.3 m/s | 1.7 |
| 1995 | 15.6°C | 10.8°C | 6.1°C | 22.0°C | 0.3°C | 136 mm | 80% | 2.1 m/s | 1.8 |
| 1994 | 12.9°C | 8.0°C | 3.0°C | 19.4°C | -3.3°C | 51 mm | 80% | 1.6 m/s | 2 |
| 1993 | 14.7°C | 9.1°C | 3.5°C | 18.9°C | -2.2°C | 46 mm | 72% | 1.6 m/s | 2.1 |
| 1992 | 13.0°C | 7.8°C | 2.6°C | 18.2°C | -2.8°C | 135 mm | 77% | 2.2 m/s | 2 |
| 1991 | 15.9°C | 9.8°C | 3.6°C | 19.6°C | -1.4°C | 51 mm | 65% | 1.9 m/s | 2.2 |
| 1990 | 13.1°C | 7.2°C | 1.4°C | 21.9°C | -6.6°C | 33 mm | 59% | 1.8 m/s | 2.6 |
| 1989 | 16.8°C | 10.4°C | 4.0°C | 20.9°C | 0.4°C | 3 mm | 62% | 1.2 m/s | 2.3 |
| 1988 | 14.1°C | 8.7°C | 3.3°C | 23.2°C | -3.6°C | 79 mm | 71% | 1.9 m/s | 2.1 |
| 1987 | 12.5°C | 7.6°C | 2.8°C | 19.1°C | -4.2°C | 83 mm | 75% | 2.8 m/s | 2.1 |
| 1986 | 16.1°C | 10.2°C | 4.3°C | 24.0°C | 1.0°C | 26 mm | 65% | 1.3 m/s | 2 |
| 1985 | 14.2°C | 8.9°C | 3.6°C | 19.1°C | -2.8°C | 47 mm | 74% | 1.4 m/s | 2 |
| 1984 | 12.3°C | 7.4°C | 2.4°C | 17.9°C | -2.2°C | 43 mm | 82% | 1.9 m/s | 2 |
| 1983 | 12.9°C | 9.2°C | 5.6°C | 18.3°C | -0.4°C | 128 mm | 89% | 2.1 m/s | — |
| 1982 | 12.6°C | 7.7°C | 2.7°C | 16.5°C | -3.0°C | 72 mm | 81% | 2 m/s | — |
| 1981 | 14.2°C | 9.8°C | 5.4°C | 19.4°C | 0.8°C | 82 mm | 84% | 1.9 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°C (mean 9°C), based on 45 years of NASA POWER data.
December averages 84 mm of rainfall in Modesto, a relatively wet time of year. The wettest on record was 237 mm in 2022.
The hottest December reached 24°C in 1986. 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 1.3°C. Daytime highs moved from 13.2°C to 14.5°C and overnight lows from 3.9°C to 5.3°C over the same span.
December is one of the cooler months of the year in Modesto and a relatively wet time of year, so plan for around 14°C daytime highs and 4°C at night.
Yes — December is the coldest month of the year in Modesto, averaging 9°C.
For December in Modesto, pack warm layers and a jacket for chilly mornings, with typical highs of 14°C and lows of 4°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 77% — quite humid.
Average wind speed in December is 1.8 m/s. The windiest December on record averaged 2.8 m/s (1987).
The wettest December on record was 2022 with 237 mm. On average, December sees 84 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 Modesto 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.
