- Matthew Hawks
- Dec 22, 2025
- 3 min read
When people think of winterizing their home, images of snowdrifts and subzero temperatures usually come to mind. But even in Southern California—where winters are mild compared to most of the country—properly preparing your doors and windows can make a noticeable difference in comfort, energy efficiency, and even your utility bills. Cool evenings, coastal moisture, desert temperature swings, and seasonal rain all take a toll on your home’s openings.
Here’s how to winterize your doors and windows the Southern California way—without overdoing it.
Why Winterizing Matters in Southern California
While daytime temperatures often stay pleasant, winter nights in Southern California can drop into the 40s or 50s, and even colder in inland or desert areas. Add in:
Chilly coastal winds
Increased rainfall
Santa Ana winds
Older homes with original windows and doors
…and suddenly, drafts and heat loss become very real issues.
Winterizing helps:
Keep indoor temperatures stable
Reduce heating costs
Prevent moisture intrusion during rainy months
Improve overall comfort without major renovations
1. Check for Drafts Around Doors and Windows
Start with a simple draft inspection. On a cool evening, place your hand around window frames and door edges. If you feel cold air sneaking in, you’ve found a problem area.
Southern California homes—especially mid-century and coastal properties—often have small gaps caused by settling, aging materials, or sun exposure.
Pro tip: A lit incense stick or candle (carefully used) can help reveal subtle air movement around frames.
2. Refresh or Replace Weatherstripping
Weatherstripping is one of the most cost-effective upgrades you can make.
Focus on:
Entry doors
Sliding glass doors (very common in SoCal homes)
French doors leading to patios or backyards
Over time, heat, UV exposure, and salty coastal air can dry out or crack weatherstripping. Replacing it helps seal gaps without affecting how your doors operate.
For sliding doors, make sure the seals are intact and the door is properly aligned—misaligned sliders are a common source of winter drafts.
3. Seal Small Gaps and Cracks
Cool winter air often enters through tiny openings you don’t notice the rest of the year.
Use caulk to seal:
Gaps between window frames and walls
Cracks around exterior door frames
Areas where old caulking has shrunk or peeled
In Southern California, flexible, paintable exterior caulk works best since it can handle temperature changes and sun exposure.
4. Don’t Ignore Sliding Doors
Sliding glass doors are a Southern California staple—but they’re also notorious for heat loss.
Winterizing sliding doors includes:
Cleaning tracks so doors close fully
Checking rollers for smooth operation
Replacing worn weather seals
Adding a snug-fitting draft blocker at the base if needed
Even small improvements can make a big difference on cool nights.
5. Upgrade Window Treatments for Cooler Nights
You don’t need heavy drapes designed for snowstorms, but the right window coverings can help retain warmth after sunset.
Consider:
Cellular or honeycomb shades
Thermal-lined curtains
Closing blinds and curtains in the evening
This is especially helpful for large windows or glass doors facing west or north, where heat loss is most noticeable after dark.
6. Prepare for Winter Rain and Moisture
Winter in Southern California often means rain rather than snow, especially from December through February.
Make sure:
Door thresholds are intact and sealed
Exterior door sweeps are in good condition
Window frames don’t show signs of water intrusion
Keeping moisture out protects against mold, wood damage, and long-term structural issues—particularly in coastal and canyon areas.
7. Consider Energy-Efficient Upgrades (When It Makes Sense)
If your doors or windows are older, winter is a good time to evaluate whether replacement might be worthwhile.
Modern options like:
Double- or triple-pane windows
Low-E glass (ideal for both winter warmth and summer heat control)
Energy-efficient patio doors
…can improve comfort year-round, not just in winter. In Southern California, these upgrades also help reduce summer cooling costs, making them a smart long-term investment.
8. Focus on Comfort, Not Overkill
The key to winterizing in Southern California is balance. You don’t need to seal your home like a mountain cabin—but you do want to eliminate unnecessary drafts and heat loss.
Small improvements add up:
Fewer cold spots
Quieter interiors during windy nights
Lower heating usage
A more comfortable home overall
Final Thoughts
Southern California winters may be mild, but that doesn’t mean your doors and windows should be ignored. With a few simple steps—sealing gaps, refreshing weatherstripping, and addressing sliding doors—you can stay warm, comfortable, and energy-efficient all season long.
Winterizing isn’t about preparing for snow—it’s about making your home work better for the climate you actually live in.
