Do Solar Panels Work in Winter?
Short answer: yes — solar panels work fine through a California winter. They run on light, not heat, and cold air actually nudges their efficiency up a little. You'll see lower monthly output from December through February — mostly from shorter days and a lower sun, not the temperature — and net metering banks your summer surplus to cover it.
Get a free estimate
- Solar panels run on light, not heat — they keep working all winter in California, and cold weather slightly raises their efficiency.
- Output is lower in winter — an illustrative ~25–35% below the peak summer month for a typical SoCal roof — mainly from shorter days and a lower sun angle, plus the occasional cloudy or rainy stretch, not the cold.
- Net metering banks your summer surplus and spends it back in winter, so a system is sized around the whole year, not any single month.
- In coastal and valley SoCal, snow is a non-issue — it only matters at mountain elevations.
Do solar panels work in winter?
Yes. It's one of the most common worries we hear, and the short version is simple: a solar array in Los Angeles or the San Fernando Valley produces power every day of the year, winter included. What changes with the seasons is how much it makes — not whether it works.
The confusion usually comes from mixing up light and heat. Solar panels make electricity from sunlight, not from warmth — so a cold, clear winter day is actually excellent solar weather. Panels even have a temperature coefficient: crystalline-silicon modules lose roughly 0.3–0.4% of their rated power for every °C above 25°C (77°F), which means they give back a little output when they cool down. On a crisp, sunny February morning a panel can briefly run a few percent above its nameplate rating.
That's the same physics running in reverse on a 100°F August afternoon, when heat quietly shaves output. We cover that side in detail in how heat affects solar panel output in LA — here, the takeaway is just that cold is on your side.
What people worry about vs what actually happens
The four winter fears we hear most — and the reality for a Southern California rooftop.
| The worry | What actually happens |
|---|---|
| “Panels stop working when it's cold” | They run on light, not heat — cold air actually nudges efficiency up a little. |
| “Winter output is basically zero” | A SoCal system produces every day; the monthly total dips (illustratively ~25–35%), it doesn't fall to nothing. |
| “I'll run out of power in winter” | Net metering banks your summer surplus so it can cover winter imports across the year. |
| “Snow will bury the panels” | In LA and the Valley snow essentially never accumulates — it only matters in the mountains. |
Why winter output is lower (it isn't the cold)
Production really does fall in winter — just not for the reason most people assume. Three things drive the dip, and temperature isn't one of them.
Shorter days
Los Angeles gets about 9 hours 55 minutes of daylight at the December solstice versus roughly 14 hours 28 minutes in June. Fewer hours of sun means fewer hours of generation, every single day.
Lower sun angle
In winter the sun stays low in the southern sky, so its light strikes a fixed rooftop at a shallower angle and passes through more atmosphere. Both weaken the energy that actually reaches your panels.
Clouds & rain
SoCal's wet season is winter. Thin high clouds trim output modestly; a heavy overcast or storm day cuts it a lot — but those days are the exception here, not the rule.
Not the temperature
Cold itself doesn't hurt — it helps slightly. Winter's cool panels convert their limited sunlight a touch more efficiently than summer's hot ones do.
Summer vs winter: an illustrative seasonal swing
Here's the rough shape of the year for a typical fixed rooftop in Southern California, normalized so the peak summer month equals 100%. Treat these as illustrative — your real numbers depend on location, roof tilt and orientation, shading, and that winter's weather.
| Season | Typical months | Output vs summer peak | What's happening |
|---|---|---|---|
| Summer | Jun–Aug | ~100% (peak) | Longest days, high sun |
| Spring | Mar–May | ~90% | Days lengthening, mild and often clear |
| Fall | Sep–Nov | ~80–90% | Days shortening, sun dropping |
| Winter | Dec–Feb | ~65–75% | Shortest days, lowest sun, wet season |
Illustrative, based on NREL PVWatts seasonal modeling for Southern California (winter runs roughly 24–37% below summer at common tilts) and our own Los Angeles installs — not a production guarantee.
How net metering evens out the year
The reason a winter dip doesn't leave you short is net metering. Your meter runs both directions: on long summer days you generate more than you use and bank the surplus as credit; on short winter days you pull more from the grid than you make and spend those credits back. Everything reconciles on an annual “true-up” statement, so a well-sized system is designed around your 12-month usage, not any one month.
How generous that banking is depends on your utility. LADWP is municipal and runs its own solar rate schedules (not NEM 3.0), so how summer exports carry into winter depends on that schedule. On SCE, PG&E and SDG&E, the newer NEM 3.0 (Net Billing Tariff) pays exports a time-varying credit that's usually well below retail — so on those utilities a home battery does more of the smoothing, storing midday output for the evening. We break down the differences in NEM 3.0 explained for California.
Leftover credit at true-up
If you finish the 12-month cycle having exported more than you used, the utility pays a small net surplus rate — typically only a few cents per kWh — and the balance resets. That's exactly why systems are sized to match annual use rather than wildly overshoot it.
What actually helps in winter
You can't add daylight, but a few things make the most of the sun you do get.
Sensible tilt
A tilt closer to your latitude (LA is ~34°) catches the low winter sun better than a near-flat roof. Most rooftops are a fixed compromise tuned for the best annual yield — which is the right goal.
Keep panels clear
Leaves, dust and debris matter more when sunlight is already scarce. SoCal rain and normal panel tilt usually self-clean the glass; only rarely is a rinse worth the effort.
Right-size the system
Size for your yearly kWh so summer surplus offsets the winter deficit. Our guide on how many panels you need walks through the math.
Add a battery (optional)
Under NEM 3.0 a battery stores cheap midday power for pricier evenings and carries you through storms — more valuable now than under old net metering.
For almost everyone here, snow isn't a factor
In coastal and valley Southern California — Los Angeles, the San Fernando Valley, most of the basin — measurable snow on a roof is essentially unheard of. Our winter weather is rain, not snow. Snow only enters the picture at mountain elevations like Big Bear or Wrightwood, and even there tilted, dark-glass panels shed and melt light snow quickly once the sun hits them.
Bottom line: winter doesn't break solar in California — it just shifts the calendar. Panels keep making power through the cold months, the cold even helps a little, and net metering carries your summer surplus across to cover the shorter days. If you're weighing the year-round math, see is solar still worth it in California in 2026?
Frequently asked
Do solar panels work in winter in California?
Yes. Solar panels generate electricity from light, not heat, so they produce power on every winter day — including cold, clear ones. You'll get less per month than in summer, mainly because winter days are shorter and the sun sits lower, but the system keeps working. In mild SoCal, that seasonal dip is modest and expected.
Does cold weather reduce solar panel efficiency?
No — cold slightly improves it. Panels have a temperature coefficient of roughly 0.3–0.4% of power per °C above 25°C (77°F), so as they cool they edge back up toward (or briefly past) their rated output. Heat is what drags output down, which we cover in how heat affects solar output in LA.
How much less do solar panels produce in winter versus summer?
For a typical Southern California rooftop, a midwinter month runs an illustrative ~25–35% below the peak summer month (very roughly 65–75% of peak). The exact figure depends on your location, roof tilt and orientation, shading, and the weather that winter — treat any single number as a ballpark, not a guarantee.
Will I run out of electricity in the winter with solar?
No. A grid-tied system pulls from the grid whenever your panels aren't covering the load, so your lights never go out. Financially, how summer exports offset winter imports depends on your utility and tariff: legacy NEM, the Net Billing Tariff (NEM 3.0) and municipal programs (LADWP) use different crediting and settlement rules — it isn't a simple bank of summer kWh applied to winter. A battery adds backup during outages and does more of the smoothing under NEM 3.0.
Do I need to worry about snow on my solar panels in Los Angeles?
For almost everyone in the LA basin and San Fernando Valley, no — measurable snow on a roof is essentially unheard of here; our winter weather is rain. Snow is only a real consideration at mountain elevations like Big Bear, and even there tilted, dark panels shed and melt light snow quickly once the sun comes out.
Should I adjust or tilt my panels for winter?
Usually not worth it. Most rooftop arrays are fixed at an angle chosen for the best year-round yield, which is the sensible target because system design normally weighs seasonal production against your annual household use — while the billing treatment depends on your utility tariff. A steeper tilt closer to your latitude captures more low winter sun, but chasing seasonal adjustments rarely pays off for a home system — right-sizing for annual use matters far more.
Related reading
Sources & methodology
Figures on this page come from the primary sources below and, where noted, from Cali Energy calculations using the stated assumptions. Rates, incentives, and program terms change; each was verified July 14, 2026.
Curious how your roof does year-round?
Send us your address and a recent bill and we'll model your production month by month — summer surplus, winter dip, and what a right-sized system covers across all 12 months.
Get a free estimatePrepared by Cali Energy, July 14, 2026. This article is for general educational purposes only and is not legal, tax, financial, engineering, or utility advice. Rates, incentives, codes, permit requirements, equipment specifications, prices, and program terms may change; figures and timelines are estimates, not guarantees. Confirm current requirements with the applicable utility, AHJ, program administrator, manufacturer, or a licensed professional. See our Content Disclaimer. Cali Energy · 19201 Parthenia St, Unit E, Northridge, CA 91324 · CSLB #1032379 (B, C-10, C-39)