December is one of the cooler months of the year in Katy, with average highs near 17.6°C and lows around 6.5°C (mean 12.1°C). It is about average for rainfall, averaging 98 mm of rainfall and 81% relative humidity across the period.
December is one of the cooler months of the year in Katy. Across 45 years of records, the warmest December in Katy was 2021 — when the month averaged 19°C — while the coldest was 1989 at 6.4°C. Typical December days reach 17.6°C with nights near 6.5°C. The long-term trend is warming, about 0.7°C per decade.
December is about average for rainfall in Katy, averaging 98 mm of rainfall. The wettest December on record was 1991 with 209 mm, while the driest was 2019 at 25 mm.
Relative humidity in Katy during December averages 81%. The most humid December was 1984 at 89%, and the least humid was 1989 at 69%.
December receives about 2.6 kWh/m²/day of solar energy in Katy. The sunniest December was 2003 at 3.3 kWh/m²/day, and the cloudiest was 1992 at 2.
Average wind speed in Katy during December is 1.9 m/s. The windiest December was 2008 at 2.3 m/s, while the calmest was 1986 at 1.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 10.8°C | 12.2°C | 11.0°C | 12.6°C | 14.7°C | +3.9°C |
| Avg High | 16.1°C | 17.6°C | 16.6°C | 18.2°C | 20.7°C | +4.6°C |
| Avg Low | 5.5°C | 6.8°C | 5.3°C | 7.0°C | 8.7°C | +3.2°C |
| Avg Rain | 98 mm | 120 mm | 92 mm | 94 mm | 78 mm | -20 mm |
December temperatures in Katy have risen by about 4.1°C between 1981–1985 and 2021–2025.
December has ranged from a record low of -12.1°C (1989) to a record high of 28.7°C (2021).
Rainfall in December is about average for rainfall, averaging 98 mm, with a wettest year of 209 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.9°C per decade while lows rose 0.6°C per decade, widening the gap between day and night.
A quieter season to visit Katy
If your dates are flexible, the more temperate months of October and April tend to be the most comfortable for visiting Katy. That said, December — with days averaging 17.6°C and nights around 6.5°C (mean 12.1°C) and higher rainfall (98 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 | 20.9°C | 14.7°C | 8.5°C | 28.4°C | -1.0°C | 29 mm | 77% | 1.7 m/s | — |
| 2024 | 21.6°C | 15.5°C | 9.3°C | 27.6°C | 1.6°C | 97 mm | 79% | 1.8 m/s | 2.8 |
| 2023 | 19.8°C | 13.6°C | 7.4°C | 27.3°C | -0.2°C | 57 mm | 76% | 1.7 m/s | 3.1 |
| 2022 | 18.8°C | 13.1°C | 7.4°C | 27.5°C | -8.8°C | 109 mm | 81% | 1.8 m/s | 2.6 |
| 2021 🔥 | 24.4°C | 19.0°C | 13.7°C | 28.7°C | 2.8°C | 47 mm | 83% | 1.9 m/s | 2.6 |
| 2020 | 18.8°C | 12.4°C | 6.0°C | 24.6°C | -1.6°C | 131 mm | 79% | 1.9 m/s | 2.8 |
| 2019 | 19.4°C | 13.0°C | 6.5°C | 27.3°C | -1.3°C | 25 mm | 74% | 1.8 m/s | 3.1 |
| 2018 | 16.8°C | 11.9°C | 7.0°C | 23.0°C | 0.8°C | 184 mm | 83% | 2 m/s | 2.7 |
| 2017 | 16.6°C | 11.2°C | 5.9°C | 26.7°C | -2.3°C | 113 mm | 80% | 1.8 m/s | 2.3 |
| 2016 | 18.8°C | 13.7°C | 8.7°C | 26.8°C | -3.5°C | 116 mm | 81% | 2 m/s | 2.3 |
| 2015 | 20.0°C | 14.5°C | 9.0°C | 27.7°C | 1.5°C | 112 mm | 85% | 2 m/s | 2.7 |
| 2014 | 18.3°C | 13.2°C | 8.1°C | 25.0°C | 1.1°C | 119 mm | 85% | 1.8 m/s | 2.1 |
| 2013 | 14.9°C | 9.6°C | 4.2°C | 25.4°C | -2.5°C | 25 mm | 84% | 1.8 m/s | 2.4 |
| 2012 | 20.9°C | 14.5°C | 8.2°C | 28.6°C | -1.5°C | 76 mm | 75% | 2 m/s | 2.7 |
| 2011 | 17.2°C | 11.9°C | 6.6°C | 25.2°C | -4.2°C | 113 mm | 82% | 1.9 m/s | 2.3 |
| 2010 | 18.9°C | 12.6°C | 6.2°C | 27.3°C | -3.2°C | 63 mm | 72% | 2.1 m/s | 2.8 |
| 2009 | 13.5°C | 8.5°C | 3.6°C | 24.9°C | -4.3°C | 140 mm | 85% | 1.9 m/s | 2.2 |
| 2008 | 17.8°C | 11.9°C | 6.0°C | 25.6°C | -2.4°C | 42 mm | 77% | 2.3 m/s | 2.4 |
| 2007 | 19.2°C | 13.0°C | 6.9°C | 26.3°C | -2.8°C | 56 mm | 80% | 1.9 m/s | 3.1 |
| 2006 | 17.0°C | 11.6°C | 6.3°C | 24.4°C | -2.7°C | 91 mm | 81% | 1.9 m/s | 2.6 |
| 2005 | 17.0°C | 10.9°C | 4.8°C | 28.3°C | -2.1°C | 79 mm | 72% | 1.9 m/s | 2.9 |
| 2004 | 16.6°C | 11.0°C | 5.4°C | 24.7°C | -3.5°C | 48 mm | 82% | 1.9 m/s | 2.9 |
| 2003 | 17.5°C | 11.2°C | 4.9°C | 22.7°C | -1.8°C | 80 mm | 78% | 2.1 m/s | 3.3 |
| 2002 | 16.4°C | 11.3°C | 6.3°C | 23.8°C | -2.0°C | 167 mm | 88% | 2.1 m/s | 2.5 |
| 2001 | 17.7°C | 12.4°C | 7.1°C | 25.4°C | -0.9°C | 141 mm | 84% | 1.8 m/s | 2.7 |
| 2000 | 13.4°C | 7.8°C | 2.1°C | 23.9°C | -3.8°C | 75 mm | 83% | 2.1 m/s | 2.6 |
| 1999 | 19.1°C | 12.4°C | 5.6°C | 26.6°C | -1.0°C | 71 mm | 74% | 2.1 m/s | 3.2 |
| 1998 | 16.8°C | 11.8°C | 6.8°C | 26.2°C | -4.0°C | 114 mm | 87% | 2 m/s | 2.6 |
| 1997 | 15.8°C | 9.9°C | 4.0°C | 24.4°C | -3.7°C | 123 mm | 82% | 1.9 m/s | 3 |
| 1996 | 18.5°C | 12.8°C | 7.2°C | 25.3°C | -6.5°C | 92 mm | 82% | 1.9 m/s | 2.7 |
| 1995 | 17.9°C | 12.4°C | 7.0°C | 28.2°C | -3.6°C | 154 mm | 81% | 1.9 m/s | 2.7 |
| 1994 | 17.7°C | 12.8°C | 7.9°C | 26.7°C | -0.2°C | 168 mm | 88% | 1.7 m/s | 2.4 |
| 1993 | 16.2°C | 11.2°C | 6.3°C | 24.4°C | -2.4°C | 73 mm | 82% | 1.9 m/s | 2.3 |
| 1992 | 18.2°C | 13.0°C | 7.9°C | 24.6°C | 2.5°C | 116 mm | 87% | 1.9 m/s | 2 |
| 1991 🌧️ | 17.1°C | 13.1°C | 9.1°C | 23.6°C | -1.4°C | 209 mm | 87% | 2 m/s | 2.1 |
| 1990 | 18.2°C | 12.2°C | 6.2°C | 26.7°C | -6.5°C | 76 mm | 76% | 2.1 m/s | 2.4 |
| 1989 ❄️ | 12.4°C | 6.4°C | 0.3°C | 24.9°C | -12.1°C | 36 mm | 69% | 1.9 m/s | 2.5 |
| 1988 | 19.6°C | 13.5°C | 7.5°C | 26.2°C | 0.0°C | 78 mm | 74% | 1.9 m/s | 2.5 |
| 1987 | 17.6°C | 12.2°C | 6.8°C | 25.8°C | -3.2°C | 134 mm | 85% | 1.9 m/s | 2.2 |
| 1986 | 13.9°C | 9.6°C | 5.3°C | 22.3°C | 0.8°C | 159 mm | 88% | 1.6 m/s | 2.2 |
| 1985 | 14.8°C | 9.1°C | 3.4°C | 22.9°C | -6.1°C | 74 mm | 83% | 1.8 m/s | 2.8 |
| 1984 | 20.2°C | 15.8°C | 11.3°C | 25.1°C | -3.5°C | 102 mm | 89% | 2.1 m/s | 2.4 |
| 1983 | 12.2°C | 7.0°C | 1.7°C | 26.8°C | -11.7°C | 86 mm | 79% | 2.2 m/s | — |
| 1982 | 17.3°C | 12.3°C | 7.2°C | 26.3°C | -3.4°C | 160 mm | 86% | 2.2 m/s | — |
| 1981 | 16.8°C | 11.3°C | 5.8°C | 24.8°C | -3.9°C | 53 mm | 81% | 2 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 17.6°C with lows near 6.5°C (mean 12.1°C), based on 45 years of NASA POWER data.
December averages 98 mm of rainfall in Katy, about average for rainfall. The wettest on record was 209 mm in 1991.
The hottest December reached 28.7°C in 2021. The coldest dipped to -12.1°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 4.1°C. Daytime highs moved from 16.3°C to 21.1°C and overnight lows from 5.9°C to 9.3°C over the same span.
December is one of the cooler months of the year in Katy and about average for rainfall, so plan for around 17.6°C daytime highs and 6.5°C at night.
Not quite — December is the 2nd coolest month in Katy, averaging 12.1°C.
For December in Katy, pack warm layers and a jacket for chilly mornings, with typical highs of 17.6°C and lows of 6.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 81% — quite humid.
Average wind speed in December is 1.9 m/s. The windiest December on record averaged 2.3 m/s (2008).
The wettest December on record was 1991 with 209 mm. On average, December sees 98 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 Katy 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.
