Do Solar Panels Work in Winter?

One of the most common misconceptions about solar panels is that they don't work in winter or cold climates. In reality, solar panels not only work during winter months—they often operate more efficiently in cold weather than in hot summer conditions. Understanding how temperature, daylight hours, and snow affect solar production helps set realistic expectations and maximize your winter solar performance.

This guide covers everything you need to know about solar panel performance in winter, from the science of cold-weather efficiency to practical tips for managing snow and optimizing production during the shortest days of the year.

Do Solar Panels Work in Winter?

Absolutely yes. Solar panels work year-round, including throughout winter and in cold climates. In fact, some of the world's largest solar installations are in cold-weather locations like Germany, Canada, and the northern United States. The key factors affecting winter solar production are daylight hours and weather conditions—not temperature.

Cold Weather Actually Improves Solar Panel Efficiency

Here's a surprising fact: solar panels become more efficient as temperatures drop. Photovoltaic cells work by converting sunlight into electricity, and this process is more efficient at lower temperatures. For every degree Celsius below 25°C (77°F), most solar panels gain approximately 0.3-0.5% in efficiency.

Efficiency comparison example:

• At 77°F (25°C): 100% rated efficiency
• At 32°F (0°C): 103-105% rated efficiency
• At 14°F (-10°C): 106-109% rated efficiency

This means on a cold, sunny winter day, your panels can actually produce more power per unit of sunlight than on a hot summer day. The reason? Excessive heat increases electrical resistance in the solar cells, reducing their efficiency. Cold temperatures minimize this resistance.

The Real Challenge: Reduced Daylight Hours

While cold improves efficiency, winter does present a production challenge: shorter days. The primary factor reducing winter solar output isn't temperature—it's the reduced number of peak sunlight hours.

Seasonal sunlight hour comparison (average U.S. location at 40° latitude):

• Summer (June): 14-15 hours of daylight, 6-7 peak sun hours
• Winter (December): 9-10 hours of daylight, 3-4 peak sun hours

This reduction in peak sun hours (the hours when sunlight is strong enough for optimal production) means your panels will produce less total energy per day in winter compared to summer, even though they're operating more efficiently during the hours they do produce.

How Cold Weather Affects Solar Panel Performance

Understanding the relationship between temperature and solar panel performance helps explain why winter production can surprise homeowners who expect poor performance in cold weather.

Temperature Coefficient Explained

Every solar panel has a "temperature coefficient" rating that indicates how much efficiency changes with temperature. This is typically measured as a percentage loss per degree Celsius above 25°C (77°F).

Typical temperature coefficients:

• Monocrystalline panels: -0.3% to -0.4% per °C
• Polycrystalline panels: -0.4% to -0.5% per °C
• Premium panels (SunPower, LG): -0.26% to -0.3% per °C

A -0.4%/°C coefficient means: For every degree Celsius above 77°F (25°C), the panel loses 0.4% efficiency. Conversely, for every degree below 77°F, it gains 0.4% efficiency (up to a point—extreme cold below -40°F can cause other issues).

Real-World Winter vs. Summer Production

While individual sunny winter days can produce impressive power, total monthly production will still be lower in winter due to fewer daylight hours and more cloudy days. Here's what to expect:

Typical production patterns (6 kW system in moderate climate):

• Best summer day (June): 35-40 kWh
• Average summer day (June): 28-32 kWh
• Best winter day (December): 20-25 kWh
• Average winter day (December): 12-18 kWh

Despite these differences, winter production still significantly offsets your electricity usage. Most solar systems are sized to over-produce in summer (building net metering credits) to compensate for lower winter production.

How Does Snow Affect Solar Panels?

Snow is one of the most common winter concerns for solar owners, but its impact is typically less severe than most people expect.

Snow Accumulation and Shedding

Solar panels are designed with a smooth, slick surface specifically to encourage snow to slide off. Additionally, dark solar cells absorb sunlight even through thin snow cover, warming the panels and accelerating melting.

How quickly snow clears from solar panels:

• Light snow (1-2 inches): Usually slides off within hours, often before noon on sunny days
• Moderate snow (3-6 inches): Clears within 1-2 days with any sun exposure
• Heavy snow (6+ inches): May take 2-4 days to clear naturally
• Wet, heavy snow: Tends to slide off faster than powdery snow

Most solar installations use a tilt angle between 30-40 degrees, which is steep enough to encourage natural snow shedding. Flatter roofs (below 20 degrees) may retain snow longer.

Should You Remove Snow from Panels?

Generally, no—it's not necessary or recommended to manually remove snow from solar panels. Here's why:

• Safety risks: Climbing on snowy roofs is dangerous and not worth the modest production gains
• Panel damage: Using hard tools can scratch panels; temperature shock from hot water can crack them
• Natural clearing: Snow typically clears naturally within days, and annual production loss is minimal
• Cost-benefit: The electricity gained rarely justifies the risk and effort

Studies show that even in heavy snow climates, annual production loss from snow cover is typically only 1-5% of total yearly output. The panels will naturally clear, and your system's annual production accounts for these occasional snow days.

The Albedo Effect: Snow Can Actually Help

Interestingly, snow-covered ground around your panels can actually boost production through the "albedo effect." Snow reflects up to 80-90% of sunlight, compared to regular ground which reflects only 10-20%. This reflected light can increase panel output by 3-8% during periods when panels are clear but ground is snow-covered.

Tips to Maximize Winter Solar Production

While you can't control daylight hours or weather, you can optimize your system for winter performance.

Optimal Panel Angle for Winter

The ideal panel tilt angle changes with seasons. Your panels were likely installed at an angle optimized for year-round production, but understanding seasonal angles helps:

• Summer optimal: Latitude minus 15 degrees (flatter angle)
• Winter optimal: Latitude plus 15 degrees (steeper angle)
• Year-round compromise: Angle equal to your latitude

Most residential installations use a fixed year-round angle. If you have adjustable ground-mount systems, increasing tilt in winter (steeper angle) can boost production by 10-20% and help snow shed faster.

Keep Panels Clean

Winter brings not just snow, but also dirt, road salt spray, and pollution that can accumulate on panels during periods of less frequent rain. Even a thin layer of grime can reduce output by 5-15%.

If you live near roads that use de-icing salt or in areas with winter pollution, consider cleaning panels once or twice during winter months on mild days. Use the same gentle methods as summer cleaning: deionized water and soft brushes.

Monitor Production Regularly

Winter is an excellent time to establish baseline production expectations. Check your monitoring system weekly to:

• Compare current production to the same period last year
• Identify if snow coverage is clearing as expected
• Spot any unusual drops that might indicate equipment issues
• Understand your system's typical winter patterns

Trim Nearby Trees

Deciduous trees that provided minimal shading in summer (when they were leafy) can actually cause more shading in winter when the sun is lower on the horizon. Bare branches may seem harmless, but they can cast surprising shadows when the sun angle is low.

Inspect for winter shading between 10 AM and 2 PM (peak production hours). Even partial shading on a few panels can significantly reduce overall system output due to how panels are wired in series.

Regional Winter Solar Performance

Winter solar performance varies significantly by location. Here's what to expect in different climates:

Northern States (Minnesota, Maine, Michigan)

• Winter production: 40-50% of summer levels
• Snow impact: Moderate—frequent snow but also many clear, cold days
• Key advantage: Excellent cold-weather efficiency gains
• Annual production: Still strong due to long summer days

Moderate Climates (New York, Pennsylvania, Colorado)

• Winter production: 55-65% of summer levels
• Snow impact: Low to moderate—occasional snow that clears quickly
• Key advantage: Good balance of sun hours and cold temperatures
• Annual production: Very consistent and predictable

Southern States (Georgia, Texas, Arizona)

• Winter production: 65-75% of summer levels
• Snow impact: Minimal to none
• Key advantage: Minimal seasonal variation
• Annual production: Highest total output

Pacific Northwest (Washington, Oregon)

• Winter production: 45-55% of summer levels
• Snow impact: Low (coastal) to moderate (inland)
• Challenge: Frequent clouds reduce overall production
• Annual production: Lower but still economically viable

Winter Solar Production Myths Debunked

Myth 1: "Solar doesn't work when it's cold"

Truth: Cold actually improves panel efficiency. The challenge is shorter days, not temperature.

Myth 2: "Snow will destroy my panels"

Truth: Solar panels are engineered to withstand significant snow loads (typically 50+ pounds per square foot). The tempered glass and frame are incredibly durable.

Myth 3: "I need to clear snow immediately"

Truth: Snow clears naturally within days. The production loss isn't worth the safety risk of roof access.

Myth 4: "Solar isn't viable in northern climates"

Truth: Germany, one of the world's solar leaders, has a climate similar to Alaska. Countries like Canada and Norway have substantial solar installations.

Myth 5: "Cloudy winter days produce zero power"

Truth: Panels still produce power on cloudy days—typically 10-25% of full capacity depending on cloud thickness. Winter cloudy-day production can actually exceed summer cloudy-day production due to better efficiency.

Conclusion

Solar panels not only work in winter—they thrive in cold weather. While reduced daylight hours mean lower total monthly production compared to summer, the efficiency gains from cold temperatures and the albedo effect from snow-covered ground help offset some of this reduction. Snow coverage is typically brief and clears naturally, with annual production loss from snow averaging only 1-5% even in heavy snow climates.

The key to successful winter solar is understanding what to expect: fewer peak sun hours but more efficient conversion of the sunlight you do receive. Modern solar systems are designed with seasonal variations in mind, typically over-producing in summer to compensate for winter shortfalls through net metering.

If you're considering solar in a cold climate, don't let winter concerns hold you back. With proper system sizing and realistic expectations, solar delivers strong ROI across all seasons and climates.