Updated: September 25, 2026 · Estimated read time: 10 minutes
Illinois winters bring:
Shorter days.
Cloudy skies.
Freezing temperatures.
Ice.
And, eventually:
Snow-covered roofs.
So it's reasonable for homeowners considering solar to ask:
Does solar actually work in an Illinois winter?
Yes.
Solar panels continue producing electricity during the winter—even when temperatures drop below freezing.
But winter solar production usually looks very different from summer production.
The interesting part is that cold weather itself isn't necessarily the problem.
Solar photovoltaic modules can actually operate more efficiently at lower temperatures.
The bigger winter challenges are:
-
Fewer daylight hours
-
Lower sun angle
-
Cloudier weather
-
Snow temporarily covering panels
That's why a properly designed Illinois solar system should be evaluated using annual production, not whether December produces as much electricity as June.
Let's break down what actually happens.
Quick Answer
Yes, solar panels work during Illinois winters.
In fact, cold temperatures can improve photovoltaic module efficiency.
However, winter production is generally lower because:
-
Days are shorter
-
The sun sits lower in the sky
-
Illinois receives less solar energy during winter
-
Cloud cover can reduce production
-
Snow can temporarily block sunlight from reaching the panels
A well-designed solar system accounts for these seasonal changes.
That means your system may produce significantly more electricity during spring and summer and less during December and January.
The question isn't:
“Will my panels produce the same amount every month?”
They won't.
The better question is:
“Will the system produce the expected amount over the entire year?”
Table of Contents
-
Do solar panels work when it's cold?
-
Why winter production is lower
-
What happens when snow covers solar panels?
-
Should you remove snow from solar panels?
-
Does snow damage solar panels?
-
Can solar panels produce on cloudy winter days?
-
Why summer production matters
-
What happens to your electric bill in winter?
-
Ameren, ComEd, and CWLP differences
-
Should you oversize solar because of winter?
-
What about batteries?
-
What happens during a winter power outage?
-
How to tell whether your system is underperforming
-
Frequently asked questions
Do Solar Panels Work When It's Cold?
Absolutely.
Solar panels don't need heat.
They need:
Light.
Photovoltaic cells convert sunlight into electricity.
That's why a bright 25°F January afternoon can still produce solar electricity.
And here's something many homeowners don't realize:
Solar panels can actually operate more efficiently in colder temperatures.
The U.S. Department of Energy explains that photovoltaic modules generally become less efficient as module temperatures rise.
So extremely hot rooftop conditions can reduce instantaneous panel efficiency.
Cold January air doesn't automatically hurt the panels' ability to convert sunlight into electricity.
But that does not mean January will outperform July.
Why?
Because temperature is only one part of solar production.
Why Is Solar Production Lower in Winter?
There are several much bigger factors.
1. Shorter Days
Illinois receives fewer daylight hours during winter.
Less daylight means fewer hours available for solar production.
That's simple physics.
A system that might have a long production window during June has a significantly shorter one during December.
2. Lower Sun Angle
The winter sun travels lower across the sky.
That changes the amount and angle of solar energy reaching your panels.
Roof orientation, pitch, nearby buildings, and trees can therefore have a different impact during winter than they do during summer.
3. Cloud Cover
Solar panels don't completely stop producing whenever a cloud appears.
Diffuse sunlight can still reach photovoltaic modules.
But heavy cloud cover reduces the amount of solar energy available.
So a dark, overcast December afternoon generally produces far less than a bright June afternoon.
4. Snow Cover
This is the obvious one.
If several inches of snow completely cover your panels:
Sunlight can't efficiently reach the photovoltaic cells.
Production can fall dramatically—or temporarily approach zero—until enough of the array becomes exposed again.
But that doesn't mean you need to climb onto the roof with a shovel.
We'll get to that shortly.
A Solar System Should Be Designed Around the Whole Year
This concept is extremely important.
Imagine an Illinois home uses:
12,000 kWh per year.
That does not mean the solar system needs to produce:
1,000 kWh every month.
Real solar production might look more like:
Lower production in December
↓
Increasing production through spring
↓
Strong production during late spring and summer
↓
Declining production through fall
↓
Lower production again during winter
The annual total matters more than making every month identical.
Illinois Shines specifically explains that systems designed around annual electricity consumption may produce extra electricity during higher-production months that helps balance lower winter production.
That's one reason homeowners shouldn't judge an entire solar system based on:
One December electric bill.
CHECK MY HOME
Wondering how much electricity solar could produce on your Illinois roof?
A useful solar design should consider:
Your annual electricity usage
Your roof
Shade
Orientation
Your utility
Seasonal production
And reasonable future electricity needs
—not just one summer electric bill.
Solar production varies based on weather, snow cover, shading, roof orientation, equipment, system design, location, utility rules, and other factors.
What Happens When Snow Covers Solar Panels?
Snow reduces production when it blocks sunlight from reaching the photovoltaic cells.
The effect depends on:
-
How much snow fell
-
Whether the array is fully covered
-
Roof and panel angle
-
Temperature
-
Wind
-
Sun exposure
-
Whether snow begins sliding from the panels
The U.S. Department of Energy notes that much of the snow on photovoltaic systems can eventually:
Melt
or:
Blow off
naturally.
Tilted rooftop solar panels can also shed snow as conditions change.
So a snowy morning doesn't necessarily mean:
“My solar system is down for the winter.”
It might simply mean:
Production is temporarily reduced until the array clears.
Should You Remove Snow From Your Solar Panels?
Usually:
Leave them alone.
The U.S. Department of Energy generally does not recommend manual snow or ice removal from photovoltaic modules.
Why?
Because removing snow incorrectly can create more problems than the temporary production loss you're trying to prevent.
You could:
-
Scratch the glass
-
Damage module frames
-
Damage wiring
-
Crack a panel
-
Damage mounting equipment
-
Slip from the roof
-
Push snow onto people or property below
And one thing should be especially obvious:
Never use a metal shovel on solar panels.
Walking or standing on panels can also damage them.
If extraordinary snow accumulation creates a legitimate structural or safety concern, contact a qualified professional rather than improvising from a ladder or roof.
“What About a Roof Rake?”
Be careful.
Even something softer than a shovel can potentially damage:
-
Glass
-
Frames
-
Wiring
-
Mounting equipment
if used incorrectly.
The Department of Energy recommends extreme caution when snow removal is genuinely necessary.
For most residential homeowners:
Losing a little temporary production is usually preferable to damaging thousands of dollars of equipment—or yourself.
Let the system clear naturally unless there's a real safety or structural reason to intervene.
Can Heavy Snow Damage Solar Panels?
Solar panels and racking installed in snowy climates should be designed for applicable structural loads.
Modern photovoltaic modules are tested for mechanical loads.
But extreme snow and ice accumulation can create significant forces.
The Department of Energy specifically notes that severe winter conditions can potentially:
-
Warp modules
-
Damage frames
-
Stress mounting systems
-
Create uneven loading
-
Cause ice-related damage
This is why the engineering side of solar matters.
A solar installation isn't simply:
Find empty roof space → attach panels.
The mounting system and roof need to support the environmental conditions the home may experience.
That's one reason the site survey and final engineering stages matter.
If you're curious what happens before installation, read our guide to what happens after signing a solar contract in Illinois.
Does Roof Pitch Affect Snow?
Yes.
Steeper panel angles generally shed snow more effectively than flatter arrays.
Gravity helps.
But residential solar arrays are usually installed to follow the existing roof pitch, so homeowners don't typically choose an extreme panel angle purely for snow removal.
System design balances:
-
Roof geometry
-
Solar exposure
-
Wind loading
-
Snow loading
-
Appearance
-
Structural requirements
-
Annual production
The goal isn't:
“Get the snow off as fast as possible.”
It's:
Build a durable solar system that performs over many Illinois seasons.
Can Solar Produce Through a Light Dusting of Snow?
Potentially.
The answer depends on how much light is actually reaching the photovoltaic cells.
A thin or partial layer may still allow some production.
A thick, opaque layer blocking the entire module can reduce it dramatically.
Modern monitoring makes this easy to observe.
You might see:
Normal production
↓
Snowstorm
↓
Very low production
↓
Panels begin clearing
↓
Production returns
That doesn't necessarily indicate an equipment failure.
Weather affects production.
Can Solar Panels Produce on Cloudy Winter Days?
Yes.
Solar panels can produce electricity using diffuse sunlight that reaches the modules through clouds.
But production is typically lower than under strong direct sunlight.
Think of it this way:
Your solar array doesn't have only two states:
SUNNY = ON
CLOUDY = OFF
Production continuously changes depending on available solar energy.
A cloudy day may produce:
Some electricity.
A bright clear day may produce:
Much more electricity.
And a snow-covered array may produce:
Very little electricity
until it clears.
Why Summer Production Matters So Much
Here's where annual solar design becomes important.
Imagine your system produces more electricity than your home needs during certain high-production months.
Depending on your utility and net-metering rules, some excess production may create credits that help offset electricity drawn from the grid later.
But Illinois utilities do not all treat solar credits identically.
That's particularly important in 2026.
New Ameren Illinois and ComEd residential systems generally operate under the newer supply-only net-metering framework.
Springfield's CWLP operates under its own municipal net-metering rules.
So while the basic concept of:
Higher summer production helping balance lower winter production
is useful, the exact financial value depends on the utility.
Read our Ameren vs. ComEd vs. CWLP Solar guide and Illinois Net Metering 2026 guide before assuming every Illinois customer receives identical credits.
Why Your First Winter Bill Might Surprise You
Imagine your solar system receives Permission to Operate in:
November.
You haven't experienced:
March
April
May
June
July
or:
August
with solar yet.
Instead, your first months are:
November → December → January.
Those are relatively low-production months.
So you might look at your first few bills and think:
“Solar isn't doing what they promised.”
Maybe.
But maybe you're evaluating an annual energy system using only the lowest-production part of the year.
That's why the better comparison is usually:
A full year of actual solar production.
If the annual system estimate was:
12,500 kWh
you shouldn't expect the production graph to deliver:
1,041 kWh every month.
Seasonality is normal.
What About CWLP Customers in Springfield?
This deserves its own section because LuNova serves Springfield homeowners.
CWLP currently operates under its own municipal net-metering program rather than Ameren or ComEd's newer structure.
CWLP also currently has an important annual-credit rule:
Unused banked credits expire during the March billing cycle.
That makes annual system sizing particularly important.
Imagine substantially oversizing a Springfield system because you want a massive summer production surplus.
If the household can't use those banked credits before the applicable expiration:
More production doesn't automatically mean more value.
That's why CWLP system sizing should account for:
-
Historical annual usage
-
Expected future usage
-
Seasonal production
-
Credit expiration
-
Roof conditions
—not simply:
“How many panels can we physically fit?”
Our 100% vs. 110% Solar Offset guide explains this in more detail.
Should You Oversize Solar Because Winter Production Is Lower?
Not automatically.
This is a common misunderstanding.
A homeowner sees lower winter production and thinks:
“Then shouldn't we just install a much bigger system?”
Maybe the home genuinely needs additional capacity.
But winter alone isn't enough justification.
Remember:
A larger array also produces more electricity during:
Spring
and:
Summer.
So a system designed purely to completely eliminate winter grid consumption might dramatically overproduce during other seasons.
The better calculation considers:
-
Annual electricity consumption
-
Annual solar production
-
Utility rules
-
Export economics
-
Roof quality
-
Future electricity needs
-
EVs
-
Electrification
-
Battery plans
That's why there is no universal:
“Illinois systems should always be 110%.”
or:
“Illinois systems should always be 120%.”
Design around the home.
Does an Electric Vehicle Change the Winter Equation?
It can.
EVs often use more energy during cold weather.
And adding an EV increases the home's total electricity consumption.
If you expect to purchase one, that future load belongs in the solar-sizing discussion.
This is particularly important if your historical electricity usage does not yet include the vehicle.
A system perfectly sized around yesterday's usage can become undersized after:
EV purchase
Heat-pump installation
or:
Other electrification.
That's why reasonable future energy needs matter.
What About Solar Batteries in Winter?
A battery doesn't generate electricity.
It stores electricity.
That's the first thing to remember.
During the day:
Solar → Home
then potentially:
Extra solar → Battery
Later:
Battery → Home
This can be useful for:
-
Backup power
-
Increased solar self-consumption
-
Certain utility-rate strategies
But winter creates an obvious limitation.
If solar production is lower because of:
-
Short days
-
Thick cloud cover
-
Snow
there may simply be less excess solar available to charge the battery.
So a battery does not magically turn:
3 kWh of winter solar production
into:
10 kWh.
It only manages the energy available.
Read our Illinois Solar Battery Guide before assuming storage solves every winter-energy challenge.
Will Solar Keep My House Running During a Winter Power Outage?
Not necessarily.
This surprises many homeowners.
A standard grid-connected solar system usually shuts down when the utility grid goes down.
Why?
Safety.
Utility workers repairing lines need to know customer solar systems aren't unexpectedly sending electricity onto the grid.
To maintain power during an outage, the home generally needs appropriately designed:
-
Battery storage
-
Backup equipment
-
Isolation equipment
-
Electrical configuration
Even then, backup capacity is limited by:
-
Battery size
-
Battery power
-
Available solar production
-
Household loads
A battery may support:
Refrigerator
Lights
Internet
Selected circuits
much longer than:
Electric heat + dryer + oven + EV charger + whole-house load simultaneously.
Backup design should be based on what you actually want to keep running.
Can Solar Heat Your House?
Solar photovoltaic panels produce:
Electricity.
They don't directly heat the home.
But that electricity can help power:
-
Heat pumps
-
Electric furnaces
-
Space heating equipment
-
Other electric loads
If you're replacing natural-gas heating with an electric heat pump, your household electricity consumption may rise significantly during colder months.
That should be considered when sizing solar.
Solar and home electrification should be planned together.
How Do You Know Whether Winter Production Is Normal?
Modern solar monitoring can help.
Look at:
-
Daily production
-
Monthly production
-
System alerts
-
Inverter status
-
Historical trends
Don't compare:
One snowy Tuesday
to:
A perfect July day.
Instead, compare actual production against realistic modeled expectations.
If your system consistently produces substantially less than expected even during:
Clear
snow-free
normal operating conditions
then further investigation may be appropriate.
Contact the installer or system-service provider.
What If Your Installer Is Gone?
This is worth mentioning because winter is often when equipment or monitoring problems become noticeable.
If your original solar company has stopped operating:
Don't assume every warranty disappeared.
Your project may still involve separate:
-
Equipment manufacturers
-
Approved Vendor
-
Lender
-
PPA owner
-
Utility
-
Monitoring provider
We built a full guide specifically for this situation:
What Happens If Your Solar Company Goes Out of Business in Illinois?
It explains Illinois Shines' stranded-customer resources, warranties, PPAs, loans, restitution, and how to identify who is actually responsible.
Should You Clean Ice Off Solar Panels?
No homeowner should be climbing onto an icy roof to increase solar production.
Ice can be particularly dangerous because it can:
-
Add weight
-
Create slippery surfaces
-
Damage components
-
Form around module edges
-
Create falling-ice hazards
If you believe ice accumulation creates an actual system or structural concern:
Contact a qualified professional.
A few temporarily lost kilowatt-hours are not worth a fall from a frozen roof.
What Should You Ask Before Installing Solar in Illinois?
Winter gives us several good questions.
1. Is winter production included in the annual estimate?
It should be.
2. What production should I expect month by month?
Ask to see the modeled seasonal curve.
3. How does my roof orientation affect winter production?
The lower winter sun can make shading more important.
4. Is the system engineered for local snow and wind loads?
It should meet applicable requirements.
5. Should I manually remove snow?
Generally no.
6. What happens during a grid outage?
Understand whether the system includes backup.
7. Does the battery recharge from solar during an outage?
Ask how the specific design works.
8. What utility assumptions are being used?
Ameren, ComEd, and CWLP aren't interchangeable.
9. Are future winter electric loads included?
Especially heat pumps and EVs.
10. How will I monitor production?
Know where to look before January arrives.
Frequently Asked Questions
Do solar panels work below freezing?
Yes. Photovoltaic panels can produce electricity below freezing, and colder module temperatures can actually improve conversion efficiency compared with very hot conditions.
Do solar panels work when covered in snow?
Production can be greatly reduced when opaque snow blocks sunlight from reaching the photovoltaic cells. Production normally returns as snow slides, melts, blows away, or otherwise clears.
Should I shovel snow off my solar panels?
Generally no. The U.S. Department of Energy warns that manual snow and ice removal can damage modules and create serious safety hazards.
Can cloudy weather still produce solar electricity?
Yes. Solar panels can produce using diffuse sunlight on cloudy days, although output is generally lower than under strong direct sunlight.
Will my solar system produce less in December than July?
Usually, yes. Illinois winter days are shorter, the sun angle is lower, and winter weather can reduce production.
Does lower winter production mean my system is undersized?
Not necessarily. Solar systems should be evaluated using expected annual production and the homeowner's annual electricity usage rather than requiring identical production every month.
Should Illinois homeowners oversize solar because of snow?
Not automatically. Oversizing can create excess production during higher-production months. Utility rules, annual usage, future energy needs, export value, and credit expiration should all be considered.
Does a battery make more solar electricity in winter?
No. Batteries store electricity; they do not generate it.
Will rooftop solar work during a winter blackout?
A standard grid-connected system generally shuts down during a grid outage unless it has properly configured backup equipment, often including battery storage.
Is solar worth considering in Illinois even though we have winter?
Winter does not prevent solar from generating electricity. Whether solar makes financial sense depends on the individual home's roof, electricity usage, utility, system cost, incentives, financing, and expected annual production.
The Biggest Winter Solar Myth
The biggest misconception is:
“Illinois is too cold for solar.”
Cold isn't the fundamental problem.
Solar technology works in cold climates.
The actual winter production challenges are:
Shorter daylight
Lower sun angle
Clouds
and sometimes:
Snow cover.
Those factors are predictable.
That's why professional solar-production modeling looks across an entire year.
A good Illinois solar proposal shouldn't pretend:
January = July.
It should explain why they're different—and still show whether the annual numbers make sense.
See What Solar Could Produce on Your Illinois Home
At LuNova Solar, we believe solar should be modeled around the conditions your home will actually experience.
That includes:
Summer.
Winter.
Shade.
Snow.
Your utility.
Your actual electricity consumption.
And your future energy needs.
SEE IF SOLAR MAKES SENSE FOR YOUR HOME
No sunshine-every-day assumptions.
Just a clearer look at what solar could realistically do for your home over the entire year.
Related Illinois Solar Guides
What Happens After You Sign a Solar Contract in Illinois?
100% vs. 110% Solar Offset: How Much Solar Does an Illinois Home Actually Need?
Ameren vs. ComEd vs. CWLP Solar
Illinois Net Metering Changed: What Homeowners Need to Know
Solar Battery or No Battery? What Illinois Homeowners Actually Need
Illinois Solar Incentives in 2026
I Got a Solar Quote. Now What?
What Happens If Your Solar Company Goes Out of Business in Illinois?
Before You Go Solar in Illinois: 7 Things Every Homeowner Should Check
Sources & References
U.S. Department of Energy — Solar Photovoltaic Hardening for Resilience: Winter Weather
Guidance covering cold-weather photovoltaic performance, snow and ice loading, snow shedding, winter system design, and safe snow-removal practices.
Illinois Shines — Consumer FAQs
Illinois-specific homeowner guidance confirming that solar systems continue producing in winter but generally experience lower seasonal production due to shorter days, lower sun angle, and snowfall.
National Renewable Energy Laboratory — Best Practices for Operation and Maintenance of Photovoltaic Systems
Technical guidance addressing snow accumulation, system design, maintenance, and snow-removal considerations.
LuNova Solar provides general educational information and does not provide engineering, structural, electrical, financial, tax, legal, or safety advice. Solar production varies by weather, snow cover, shading, location, roof orientation, equipment, utility rules, system design, and household electricity use. Do not climb onto a roof or attempt to remove snow or ice from photovoltaic equipment unless properly qualified and equipped to do so.