December is one of the cooler months of the year in Irvine, with average highs near 5.8°C and lows around 2.5°C (mean 4.2°C). It is a relatively wet time of year, averaging 128 mm of rainfall and 94% relative humidity across the period.
December is one of the cooler months of the year in Irvine. Across 45 years of records, the warmest Decembers in Irvine were 1988 and 2015 — when the month averaged 6.5°C — while the coldest was 1981 at -0.2°C. Typical December days reach 5.8°C with nights near 2.5°C. The long-term trend is warming, about 0.3°C per decade.
December is a relatively wet time of year in Irvine, averaging 128 mm of rainfall. The wettest December on record was 2015 with 264 mm, while the driest was 1995 at 40 mm.
Relative humidity in Irvine during December averages 94%. The most humid December was 2002 at 96%, and the least humid was 1990 at 92%.
December receives about 0.4 kWh/m²/day of solar energy in Irvine. The sunniest December was 2010 at 0.5 kWh/m²/day, and the cloudiest were 2019, 2021 and 2023, among others at 0.3.
Average wind speed in Irvine during December is 4.5 m/s. The windiest December was 2013 at 6.4 m/s, while the calmest was 2010 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 3.9°C | 3.7°C | 4.2°C | 4.5°C | 4.9°C | +1°C |
| Avg High | 5.5°C | 5.3°C | 5.9°C | 6.2°C | 6.5°C | +1°C |
| Avg Low | 2.2°C | 2.0°C | 2.5°C | 2.8°C | 3.3°C | +1.1°C |
| Avg Rain | 122 mm | 135 mm | 112 mm | 141 mm | 132 mm | +10 mm |
December temperatures in Irvine have risen by about 1.6°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -8.2°C (1995) to a record high of 12.4°C (2025).
Rainfall in December is a relatively wet time of year, averaging 128 mm, with a wettest year of 264 mm.
A quieter season to visit Irvine
If your dates are flexible, the more temperate months of July and August tend to be the most comfortable for visiting Irvine. That said, December — with days averaging 5.8°C and nights around 2.5°C (mean 4.2°C) and higher rainfall (128 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 | 7.1°C | 5.6°C | 4.1°C | 12.4°C | -1.0°C | 129 mm | 95% | 4.3 m/s | — |
| 2024 | 7.9°C | 6.1°C | 4.4°C | 11.6°C | -1.1°C | 125 mm | 94% | 5 m/s | 0.4 |
| 2023 | 6.8°C | 5.3°C | 3.7°C | 10.9°C | -0.8°C | 175 mm | 94% | 5.1 m/s | 0.3 |
| 2022 | 4.9°C | 3.2°C | 1.5°C | 11.6°C | -3.0°C | 108 mm | 94% | 3.9 m/s | 0.4 |
| 2021 | 6.3°C | 4.6°C | 3.0°C | 10.7°C | -0.2°C | 126 mm | 95% | 3.8 m/s | 0.3 |
| 2020 | 5.8°C | 4.3°C | 2.9°C | 10.9°C | -0.9°C | 129 mm | 95% | 4.2 m/s | 0.4 |
| 2019 | 6.6°C | 5.2°C | 3.7°C | 11.2°C | -0.2°C | 129 mm | 95% | 4.7 m/s | 0.3 |
| 2018 | 6.7°C | 5.1°C | 3.5°C | 10.3°C | 0.0°C | 117 mm | 95% | 4.2 m/s | 0.4 |
| 2017 | 5.9°C | 4.1°C | 2.4°C | 11.2°C | -2.1°C | 111 mm | 95% | 3.9 m/s | 0.4 |
| 2016 | 7.7°C | 6.0°C | 4.4°C | 11.8°C | -0.6°C | 83 mm | 95% | 4.6 m/s | 0.3 |
| 2015 🌧️ | 8.6°C | 6.5°C | 4.4°C | 12.1°C | 0.4°C | 264 mm | 93% | 6.1 m/s | 0.3 |
| 2014 | 6.0°C | 4.4°C | 2.8°C | 10.5°C | -0.7°C | 136 mm | 93% | 4.7 m/s | 0.4 |
| 2013 | 7.5°C | 5.7°C | 3.9°C | 11.1°C | -0.9°C | 159 mm | 93% | 6.4 m/s | 0.3 |
| 2012 | 5.0°C | 3.3°C | 1.5°C | 9.9°C | -1.6°C | 177 mm | 95% | 4.4 m/s | 0.4 |
| 2011 | 6.4°C | 4.7°C | 2.9°C | 10.6°C | -0.8°C | 187 mm | 93% | 5.7 m/s | 0.3 |
| 2010 | 1.9°C | 0.0°C | -1.9°C | 7.1°C | -5.5°C | 43 mm | 95% | 2.8 m/s | 0.5 |
| 2009 | 3.8°C | 2.1°C | 0.3°C | 9.6°C | -4.2°C | 77 mm | 94% | 3.3 m/s | 0.4 |
| 2008 | 5.1°C | 3.4°C | 1.8°C | 10.0°C | -1.5°C | 96 mm | 94% | 3.6 m/s | 0.4 |
| 2007 | 6.5°C | 4.7°C | 3.0°C | 11.4°C | -1.5°C | 114 mm | 94% | 4.6 m/s | 0.4 |
| 2006 | 7.5°C | 5.6°C | 3.7°C | 11.7°C | 0.3°C | 190 mm | 94% | 5.1 m/s | 0.4 |
| 2005 | 6.3°C | 4.6°C | 2.9°C | 10.5°C | -1.4°C | 80 mm | 95% | 3.7 m/s | 0.4 |
| 2004 | 7.2°C | 5.5°C | 3.8°C | 10.4°C | -2.0°C | 120 mm | 94% | 4.9 m/s | 0.4 |
| 2003 | 6.5°C | 4.5°C | 2.5°C | 10.4°C | -3.3°C | 126 mm | 94% | 4.1 m/s | 0.4 |
| 2002 | 5.0°C | 3.6°C | 2.3°C | 9.9°C | -0.7°C | 84 mm | 96% | 3.7 m/s | 0.4 |
| 2001 | 5.4°C | 3.4°C | 1.4°C | 10.7°C | -2.3°C | 79 mm | 93% | 3.9 m/s | 0.4 |
| 2000 | 5.6°C | 4.4°C | 3.3°C | 10.7°C | -2.7°C | 156 mm | 94% | 4.7 m/s | 0.3 |
| 1999 | 4.9°C | 3.2°C | 1.4°C | 10.2°C | -4.1°C | 207 mm | 93% | 5 m/s | 0.3 |
| 1998 | 7.0°C | 5.1°C | 3.3°C | 11.4°C | -1.7°C | 112 mm | 94% | 4.9 m/s | 0.3 |
| 1997 | 6.5°C | 5.0°C | 3.5°C | 10.4°C | -1.6°C | 148 mm | 95% | 4.5 m/s | 0.3 |
| 1996 | 3.7°C | 2.3°C | 0.9°C | 8.5°C | -2.2°C | 90 mm | 95% | 3.9 m/s | 0.4 |
| 1995 | 2.6°C | 1.0°C | -0.6°C | 10.6°C | -8.2°C | 40 mm | 95% | 3.6 m/s | 0.3 |
| 1994 | 6.6°C | 4.9°C | 3.3°C | 12.1°C | -1.2°C | 197 mm | 93% | 5.3 m/s | 0.3 |
| 1993 | 5.0°C | 3.2°C | 1.4°C | 10.1°C | -2.9°C | 197 mm | 94% | 5.1 m/s | 0.3 |
| 1992 | 4.9°C | 3.5°C | 2.0°C | 8.8°C | -0.9°C | 105 mm | 94% | 4.1 m/s | 0.4 |
| 1991 | 6.6°C | 4.9°C | 3.2°C | 10.5°C | -1.0°C | 114 mm | 94% | 4.3 m/s | 0.4 |
| 1990 | 5.1°C | 3.4°C | 1.6°C | 9.9°C | -1.8°C | 139 mm | 92% | 4.7 m/s | 0.3 |
| 1989 | 4.2°C | 2.6°C | 1.1°C | 9.9°C | -2.0°C | 74 mm | 95% | 3.6 m/s | 0.4 |
| 1988 🔥 | 8.0°C | 6.5°C | 5.0°C | 10.5°C | -0.3°C | 98 mm | 94% | 5.3 m/s | 0.3 |
| 1987 | 6.0°C | 4.5°C | 2.9°C | 10.5°C | -2.1°C | 103 mm | 95% | 4.2 m/s | 0.3 |
| 1986 | 5.9°C | 4.1°C | 2.3°C | 10.8°C | -1.7°C | 218 mm | 93% | 5.2 m/s | 0.3 |
| 1985 | 6.2°C | 4.7°C | 3.1°C | 11.8°C | -5.5°C | 149 mm | 94% | 4.6 m/s | 0.3 |
| 1984 | 6.1°C | 4.5°C | 2.8°C | 10.0°C | -1.2°C | 121 mm | 94% | 4.3 m/s | 0.3 |
| 1983 | 6.7°C | 4.9°C | 3.1°C | 10.5°C | -1.3°C | 139 mm | 94% | 5.1 m/s | — |
| 1982 | 5.0°C | 3.2°C | 1.5°C | 9.9°C | -2.0°C | 153 mm | 93% | 4.7 m/s | — |
| 1981 ❄️ | 1.5°C | -0.2°C | -1.9°C | 9.4°C | -7.2°C | 47 mm | 94% | 3.6 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 5.8°C with lows near 2.5°C (mean 4.2°C), based on 45 years of NASA POWER data.
December averages 128 mm of rainfall in Irvine, a relatively wet time of year. The wettest on record was 264 mm in 2015.
The hottest December reached 12.4°C in 2025. The coldest dipped to -8.2°C in 1995.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 1.6°C. Daytime highs moved from 5.1°C to 6.6°C and overnight lows from 1.7°C to 3.3°C over the same span.
December is one of the cooler months of the year in Irvine and a relatively wet time of year, so plan for around 5.8°C daytime highs and 2.5°C at night.
Not quite — December is the 3rd coolest month in Irvine, averaging 4.2°C.
For December in Irvine, pack warm layers and a jacket for chilly mornings, with typical highs of 5.8°C and lows of 2.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 94% — quite humid.
Average wind speed in December is 4.5 m/s. The windiest December on record averaged 6.4 m/s (2013).
The wettest December on record was 2015 with 264 mm. On average, December sees 128 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 Irvine 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.
