As winter approaches, many Houstonians wonder what to expect from the Houston weather in December. While the city typically enjoys mild winters, sudden cold fronts and fluctuating temperatures can catch residents off guard.
In this article, we’ll break down the full weather forecast for December 2025 and explore how these conditions could impact your home comfort systems. Plus, 75 Degree AC shares expert tips and smart HVAC solutions to help you stay warm, energy-efficient, and prepared all season long.
Table of Contents
What’s Special About Houston Weather in December 2025?
Houston Weather in December brings mild winter weather, with warm, sunny days interspersed with occasional cold snaps. Temperatures typically range from 54°F (12°C) at night to 70°F–73°F (21°C–23°C) during the day, making heating, ventilation, and air conditioning (HVAC) systems essential for comfort. High humidity and indoor air quality can impact health and well-being.
Houston Weather in December 2025 forecast
Curious about what to expect from the Houston weather in December 2025? Forecasts suggest a month of mild days, cool nights, and a few wet spells. Whether you’re planning holiday activities or prepping your home systems, staying ahead of the weather is key.
Average Temperatures & Weather Patterns
Houston Weather in December typically features moderate daytime highs ranging from 65°F to 68°F (18°C to 20°C), with nighttime lows dropping to 38°F to 47°F (3°C to 8°C). In December 2025, early forecasts suggest slightly warmer-than-average conditions due to lingering El Niño effects.
| Dec Date | Avg High (°F) | Avg Low (°F) |
|---|---|---|
| 1 | 68 | 47 |
| 2 | 68 | 47 |
| 3 | 67 | 47 |
| 4 | 67 | 46 |
| 5 | 67 | 48 |
| 6 | 67 | 48 |
| 7 | 67 | 45 |
| 8 | 67 | 44 |
| 9 | 67 | 44 |
| 10 | 67 | 43 |
| 11 | 67 | 44 |
| 12 | 66 | 42 |
| 13 | 66 | 42 |
| 14 | 66 | 41 |
| 15 | 66 | 41 |
| 16 | 66 | 40 |
| 17 | 66 | 40 |
| 18 | 66 | 40 |
| 19 | 65 | 39 |
| 20 | 65 | 39 |
| 21 | 65 | 38 |
| 22 | 65 | 38 |
| 23 | 65 | 38 |
| 24 | 65 | 38 |
| 25 | 65 | 38 |
| 26 | 65 | 38 |
| 27 | 65 | 38 |
| 28 | 65 | 38 |
| 29 | 65 | 38 |
| 30 | 65 | 38 |
| 31 | 65 | 38 |
Forecast based on historical data from Weather.com and NOAA.
Tip: Check your thermostat and ensure your heating system is functional before temperatures drop significantly.
Rainfall & Humidity
In Houston, December typically experiences an average rainfall of approximately 3.0 to 3.5 inches. During this month, the relative humidity levels generally range between 65% and 75%, creating a moderately humid environment. While the outdoor humidity is relatively comfortable, indoor spaces can often feel damp if proper HVAC systems are not in place to regulate moisture levels.
Without adequate ventilation and dehumidification, this indoor dampness may lead to discomfort and potential issues such as mold growth or musty odors. Therefore, effective humidity control is essential for maintaining a comfortable and healthy indoor atmosphere throughout December in Houston.
Solution: Use a dehumidifier and schedule regular air duct cleaning to control humidity. 75DegreeAC offers professional cleaning services to address this issue.
Air Quality & Seasonal Allergens
Cooler months often lead to trapped indoor air and a rise in allergens such as dust mites, mold spores, and pet dander. Ensuring good air circulation and regular HVAC maintenance becomes crucial during this time.
Advice: Install HEPA air purifiers and clean ventilation systems regularly. 75DegreeAC’s Indoor Air Quality (IAQ) services help eliminate allergens for a healthier home environment.
Tips from 75 Degree AC to Prepare Your Home for Winter
As the Houston weather in December brings shifting conditions, preparation is key. Our HVAC specialists at 75 Degree AC have compiled practical, easy-to-follow winter tips to help you protect your home and optimize comfort before the next cold front hits.
Things to Do Before a Cold Front
As Houston weather in December can bring unexpected cold fronts, consider the following preparations:
- Schedule a full HVAC system inspection
- Seal air leaks around windows and doors
- Upgrade to a programmable or smart thermostat
- Check and replace air filters
- Inspect insulation in attics and crawlspaces
- Ensure carbon monoxide detectors are functioning
- Run your heating system early to test its performance
Energy-Saving Tips for Winter
Winter energy bills can climb quickly, but small changes make a big difference. To stay warm while saving money, seal air leaks, use a programmable thermostat.
- Set your thermostat to 68°F when home, and lower when away
- Use ceiling fans in reverse mode to distribute warm air
- Open curtains during sunny days to naturally heat rooms
- Close blinds and curtains at night to retain heat
- Schedule HVAC service with 75 Degree AC for maximum efficiency
How Houston Weather in December Impacts Heating Systems
Houston weather in December isn’t just about cooler air, it creates unique challenges for your Heating system. From inconsistent temperatures to indoor air quality concerns, understanding how the weather affects your heating and cooling is the first step to staying comfortable all season long.
Why Houston Still Needs Air Conditioning in Winter?
Houston weather in December often features mild daytime temps that can still necessitate light cooling, especially in sunlit or poorly insulated homes. Smart thermostats can help strike a balance between heating during chilly mornings and cooling during warm afternoons.
Common Heating AC Issues in December
With Houston’s variable weather patterns, it’s common to experience:
- Uneven Heating – Some rooms feel colder than others, often due to duct leaks or blocked vents and higher energy bills.
- Thermostat Malfunctions – Inaccurate readings or unresponsive controls can lead to inefficient heating.
- Dirty Air Filters – Clogged filters restrict airflow, making the system work harder and increasing energy bills.
- Ignition or Pilot Light Problems – Especially in gas furnaces, cold weather can trigger issues with ignition systems.
- Frozen Coils or Pipes – Sudden temperature drops can cause condensation to freeze, especially in poorly maintained units
Recommended HVAC Services for December in Houston
| Service Type | Why It’s important | Provide by 75 Degree AC |
|---|---|---|
| Heating Services Houston | Ensures efficiency, avoids winter breakdowns | Yes |
| Duct Cleaning & Air Purification | Reduces allergens, improves indoor air quality | Yes |
| Smart Thermostat Installation | Enhances comfort and energy savings | Yes |
| Ductless Mini-Split Solutions | Great for specific zones with inconsistent temperature | Yes |
| Indoor Air Quality Testing | Identifies hidden allergens and pollutants | Yes |
Frequently Asked Questions (FAQ)
Still curious about how Houston weather in December affects? Here are answers to some of the most common questions homeowners ask during this season.
Is December cold in Houston?
Not extremely. Houston weather in December is generally mild compared to most U.S. cities, though a few cold nights are typical. Be prepared for occasional dips below 50°F. Be prepared for occasional dips below 50°F.
Do I need to service my AC unit in winter?
Absolutely. Despite the relatively mild Houston weather in December, seasonal checkups improve performance, extend lifespan, and prevent costly repairs.
How can I improve indoor air quality during winter?
With Houston weather in December leading to more time spent indoors, it’s essential to clean air ducts, use HEPA filters, run air purifiers, and schedule an IAQ assessment with a professional.
Should I upgrade to a smart thermostat this season?
Yes, especially with fluctuating Houston weather in December. Smart thermostats help maintain consistent comfort, reduce energy usage, and automate heating and cooling schedules.
What temperature should I set my thermostat in December?
Energy experts recommend 68°F when you’re home and awake, and lowering it 7–10°F while you’re asleep or away for optimal savings.
Conclusion
While Houston weather in December may not be harsh, its unpredictability makes HVAC preparedness essential. With mild days and chilly nights, keeping your home comfortable requires proactive care. Let 75 Degree AC help you stay cozy, efficient, and worry-free this winter.
Ready to winter-proof your home? Contact 75 Degree AC today and book your seasonal HVAC tune-up!
