December is one of the cooler months of the year in Plano, with average highs near 13.6°C and lows around 2.2°C (mean 7.9°C). It is one of the drier months, averaging 68 mm of rainfall and 75% relative humidity across the period.
December is one of the cooler months of the year in Plano. Across 45 years of records, the warmest December in Plano was 2021 — when the month averaged 15.4°C — while the coldest was 1983 at 1.5°C. Typical December days reach 13.6°C with nights near 2.2°C. The long-term trend is warming, about 0.9°C per decade.
December is one of the drier months in Plano, averaging 68 mm of rainfall. The wettest December on record was 1991 with 229 mm, while the driest was 2025 at 2 mm.
Relative humidity in Plano during December averages 75%. The most humid December was 1991 at 86%, and the least humid was 2005 at 57%.
December receives about 2.4 kWh/m²/day of solar energy in Plano. The sunniest Decembers were 2003, 2004 and 2005 at 2.9 kWh/m²/day, and the cloudiest were 1992 and 2014 at 1.9.
Average wind speed in Plano during December is 3.1 m/s. The windiest December was 2008 at 3.8 m/s, while the calmest was 1986 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 6.3°C | 7.8°C | 7.3°C | 8.4°C | 10.8°C | +4.5°C |
| Avg High | 11.8°C | 13.3°C | 13.3°C | 13.9°C | 16.8°C | +5°C |
| Avg Low | 0.7°C | 2.3°C | 1.4°C | 2.9°C | 4.8°C | +4.1°C |
| Avg Rain | 63 mm | 98 mm | 56 mm | 64 mm | 54 mm | -8 mm |
December temperatures in Plano have risen by about 4.8°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -17.6°C (1989) to a record high of 28.9°C (2005).
Rainfall in December is one of the drier months, averaging 68 mm, with a wettest year of 229 mm.
A quieter season to visit Plano
If your dates are flexible, the more temperate months of May and October tend to be the most comfortable for visiting Plano. That said, December — with days averaging 13.6°C and nights around 2.2°C (mean 7.9°C) and moderate rainfall (68 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 | 16.8°C | 10.6°C | 4.3°C | 28.3°C | -3.5°C | 2 mm | 71% | 3.1 m/s | — |
| 2024 | 17.0°C | 11.3°C | 5.6°C | 24.1°C | -0.8°C | 94 mm | 76% | 2.8 m/s | 2.4 |
| 2023 | 16.2°C | 10.1°C | 4.0°C | 24.4°C | -2.0°C | 73 mm | 72% | 2.8 m/s | 2.8 |
| 2022 | 13.9°C | 8.8°C | 3.7°C | 23.5°C | -11.0°C | 44 mm | 75% | 2.9 m/s | 2.3 |
| 2021 🔥 | 21.4°C | 15.4°C | 9.3°C | 27.7°C | -0.7°C | 12 mm | 72% | 3.2 m/s | 2.5 |
| 2020 | 15.4°C | 8.7°C | 1.9°C | 24.0°C | -4.2°C | 102 mm | 69% | 3.2 m/s | 2.6 |
| 2019 | 15.3°C | 9.2°C | 3.1°C | 21.3°C | -3.2°C | 23 mm | 73% | 2.7 m/s | 2.7 |
| 2018 | 12.6°C | 7.9°C | 3.2°C | 19.6°C | -2.5°C | 96 mm | 82% | 3.2 m/s | 2.4 |
| 2017 | 13.8°C | 8.2°C | 2.7°C | 27.1°C | -6.1°C | 74 mm | 67% | 2.9 m/s | 2.3 |
| 2016 | 14.1°C | 8.7°C | 3.3°C | 25.0°C | -8.4°C | 18 mm | 69% | 3.2 m/s | 2 |
| 2015 | 15.6°C | 10.0°C | 4.5°C | 23.3°C | -2.5°C | 124 mm | 83% | 3 m/s | 2.8 |
| 2014 | 14.3°C | 9.8°C | 5.3°C | 24.9°C | -2.6°C | 38 mm | 78% | 2.9 m/s | 1.9 |
| 2013 | 10.8°C | 5.0°C | -0.8°C | 21.2°C | -10.0°C | 61 mm | 79% | 2.7 m/s | 2.4 |
| 2012 | 16.0°C | 9.6°C | 3.3°C | 27.7°C | -7.0°C | 52 mm | 64% | 3.2 m/s | 2.6 |
| 2011 | 12.7°C | 7.5°C | 2.3°C | 20.2°C | -6.0°C | 113 mm | 79% | 2.8 m/s | 2.1 |
| 2010 | 14.1°C | 7.9°C | 1.7°C | 25.7°C | -5.4°C | 44 mm | 67% | 3.3 m/s | 2.7 |
| 2009 | 9.6°C | 4.6°C | -0.4°C | 21.2°C | -7.0°C | 56 mm | 81% | 3 m/s | 2.3 |
| 2008 | 13.9°C | 7.3°C | 0.8°C | 24.4°C | -6.4°C | 16 mm | 64% | 3.8 m/s | 2.5 |
| 2007 | 14.6°C | 8.1°C | 1.6°C | 26.0°C | -5.6°C | 53 mm | 74% | 3.1 m/s | 2.5 |
| 2006 | 14.7°C | 8.7°C | 2.7°C | 24.4°C | -6.9°C | 78 mm | 73% | 3.2 m/s | 2.7 |
| 2005 | 14.5°C | 7.9°C | 1.3°C | 28.9°C | -7.3°C | 7 mm | 57% | 3.1 m/s | 2.9 |
| 2004 | 13.8°C | 7.9°C | 2.0°C | 22.0°C | -7.6°C | 19 mm | 77% | 3.1 m/s | 2.9 |
| 2003 | 15.6°C | 9.0°C | 2.4°C | 22.8°C | -3.2°C | 26 mm | 67% | 3.7 m/s | 2.9 |
| 2002 | 13.8°C | 8.2°C | 2.6°C | 21.3°C | -4.9°C | 109 mm | 79% | 3.1 m/s | 2.3 |
| 2001 | 14.7°C | 8.9°C | 3.1°C | 24.2°C | -4.3°C | 104 mm | 73% | 2.9 m/s | 2.6 |
| 2000 | 7.7°C | 2.7°C | -2.3°C | 19.3°C | -9.0°C | 87 mm | 82% | 3.1 m/s | 2.4 |
| 1999 | 15.6°C | 9.1°C | 2.6°C | 25.7°C | -4.0°C | 76 mm | 67% | 3.5 m/s | 2.8 |
| 1998 | 12.9°C | 7.7°C | 2.5°C | 25.1°C | -6.6°C | 122 mm | 81% | 2.9 m/s | 2.4 |
| 1997 | 12.0°C | 6.4°C | 0.9°C | 20.4°C | -5.1°C | 162 mm | 79% | 3 m/s | 2.4 |
| 1996 | 14.4°C | 8.2°C | 2.0°C | 23.2°C | -6.9°C | 22 mm | 80% | 3.4 m/s | 2.7 |
| 1995 | 14.1°C | 8.2°C | 2.3°C | 26.5°C | -7.1°C | 57 mm | 72% | 3.2 m/s | 2.3 |
| 1994 | 13.5°C | 8.6°C | 3.6°C | 22.8°C | -4.2°C | 85 mm | 86% | 2.4 m/s | 2.1 |
| 1993 | 13.0°C | 7.7°C | 2.3°C | 21.8°C | -4.5°C | 69 mm | 79% | 3.2 m/s | 2.4 |
| 1992 | 13.1°C | 7.9°C | 2.8°C | 23.3°C | -3.3°C | 116 mm | 82% | 3.1 m/s | 1.9 |
| 1991 🌧️ | 12.5°C | 8.3°C | 4.0°C | 21.8°C | -2.7°C | 229 mm | 86% | 3.1 m/s | 2.2 |
| 1990 | 11.9°C | 6.0°C | 0.2°C | 22.5°C | -11.1°C | 46 mm | 75% | 3.2 m/s | 2.4 |
| 1989 | 9.2°C | 2.9°C | -3.4°C | 22.4°C | -17.6°C | 10 mm | 61% | 3.2 m/s | 2.8 |
| 1988 | 14.0°C | 7.9°C | 1.8°C | 20.9°C | -4.7°C | 72 mm | 74% | 2.9 m/s | 2.4 |
| 1987 | 12.5°C | 7.1°C | 1.6°C | 22.4°C | -5.8°C | 115 mm | 80% | 3.2 m/s | 2.1 |
| 1986 | 11.3°C | 6.5°C | 1.8°C | 18.6°C | -4.0°C | 61 mm | 83% | 2.3 m/s | 2.1 |
| 1985 | 11.0°C | 4.9°C | -1.2°C | 21.1°C | -6.9°C | 37 mm | 78% | 3 m/s | 2.8 |
| 1984 | 16.0°C | 10.7°C | 5.3°C | 22.8°C | -4.8°C | 140 mm | 85% | 3.2 m/s | 2 |
| 1983 ❄️ | 6.8°C | 1.5°C | -3.8°C | 22.3°C | -14.5°C | 24 mm | 72% | 3.4 m/s | — |
| 1982 | 13.3°C | 8.0°C | 2.6°C | 25.5°C | -6.4°C | 100 mm | 78% | 3.2 m/s | — |
| 1981 | 12.3°C | 6.9°C | 1.4°C | 20.7°C | -6.2°C | 5 mm | 79% | 3.2 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 13.6°C with lows near 2.2°C (mean 7.9°C), based on 45 years of NASA POWER data.
December averages 68 mm of rainfall in Plano, one of the drier months. The wettest on record was 229 mm in 1991.
The hottest December reached 28.9°C in 2005. The coldest dipped to -17.6°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 4.8°C. Daytime highs moved from 11.9°C to 17.1°C and overnight lows from 0.9°C to 5.4°C over the same span.
December is one of the cooler months of the year in Plano and one of the drier months, so plan for around 13.6°C daytime highs and 2.2°C at night.
Not quite — December is the 2nd coolest month in Plano, averaging 7.9°C.
For December in Plano, pack warm layers and a jacket for chilly mornings, with typical highs of 13.6°C and lows of 2.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 75% — quite humid.
Average wind speed in December is 3.1 m/s. The windiest December on record averaged 3.8 m/s (2008).
The wettest December on record was 1991 with 229 mm. On average, December sees 68 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 Plano 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.
