How Does Snow On Solar Panels Affect Their Efficiency?

When you think about the most suitable environment for solar panels, you probably imagine a place with a warm climate and long, sunny days. But what about cities known for cold winters? Do solar panels work in winter in cities like Chicago? You’d be surprised to discover that solar mechanisms can even perform better during the cold months.

This article will explore how snow on solar panels can affect their efficiency, debunk some common myths, and unveil strategies to maximize winter performance.

Do Solar Panels Work in Winter?

Like many other electronic devices, solar panels can overheat when temperatures get too high. They even may fail and shut down completely when the temperatures are extremely high.

So, the good news is you can generate solar power in winter. If there is light snow, you have nothing to worry about. It has a high albedo, reflecting the sunlight, which means your panels will consume light from multiple angles. However, the excessive amount of snow on solar panels can negatively affect energy production, and here’s how:

  • Blocked sunlight: A blanket of snow reduces the amount of light reaching the cells, hindering their ability to convert light into electricity. It can lead to a 20-30% efficiency drop in energy production.
  • Weight of snow: Large snow accumulations can add significant weight to the panels, potentially stressing the mounting system and even causing damage in extreme cases.

Solar panels in winter can still generate electricity, especially when the season is predominantly dry. It’s no secret that panels are most effective in a dry climate with mid-range temperatures (from 15°F up to 90°F). Chicago’s winters fit this temperature range.

Solar freezing starts after the temperature falls below -5°F. But that’s not the actual freezing that happens with water. Solar cells aren’t filled with a liquid that solidifies at cold temperatures. However, their performance will slightly reduce during the extra-cold temperatures.

Here’s the thing: solar panels and snow are not the best allies, so many solar installers recommend installing panels at a steeper angle. A tilt should be close to the location’s latitude to achieve the maximum sunlight on panels.

Pro tip: Illinois residents should place panels angled at 40°-45°. That is a steep tilt, so most snow will naturally fall from the panels. If possible, install a solar tracker that will slightly turn panels so they will receive the maximum sunlight. It will help you collect more electricity and melt some of the snow on solar panels.

Melting and Drifting Patterns

Chicago is known for its harsh winters and murky mid-season weather, with pullbacks to the cold and snow even in April. Thus, cleaning snow off solar panels will be a routine process for Illinois residents.

A graph showing cloud cover categories in Chicago over the course of the year

Source: Weatherspark

Chicago experiences colder temperatures, with an average January temperature of 29°F and 38 inches of snowfall. It leads to slower snowmelt compared to regions with warmer winters. Strong winds can help you to remove solar panels’ snow. If you face windless weather, remove excessive snow from panels using soft brushes or microfiber brooms.

Looking for the right solar system able to endure any weather conditions in Illinois? Get your free solar quote in a matter of minutes!

A snow guard for solar panels is an additional tool that can help you prevent excessive snow accumulation. A snow guard is a physical barrier strategically installed on the surface or frame of a solar panel. Such barriers help manage snow accumulation and prevent it from affecting the efficiency of your solar panel system.

Geographic Considerations and Panel’s Structural Integrity

On average, Chicago receives 38 inches of snowfall annually. Most snowfall occurs between December and February, with lighter snow possibly occurring in March and November. Therefore, in Chicago, solar panels are covered in snow for 3-5 months annually.

While Illinois is not the coldest state in the U.S., the winter temperatures still warrant concern for the solar system’s structural integrity. The weight of sediments depends on their water content. Fresh snow or snow in cold regions is usually airier. At the same time, snow that has started to melt becomes more watery. It increases the density and weight per square foot.

Chicago’s colder temperatures can lead to slower snowmelt, potentially extending the period of snow cover on panels. However, this also means the snow might be lighter and less impactful on efficiency than wet, heavy snow in warmer regions.

A young woman cleaning solar panels covered with snow

It’s safe to assume that 1 inch of average snow accumulation weighs 1.04 pounds per square foot. Considering a solar panel might span several square feet, even a moderate accumulation can translate to significant weight.

To determine whether the snow on solar panels will harm your solar system, check a panel’s instructions and warranty to determine its designated snow load capacity. You should pick models that support a sufficient load of 40 to 100 pounds per square foot.

Heating Systems

Solar panels covered in snow do work, but there’s a catch: only a light dusting of snow allows them to generate energy. Therefore, we recommend speeding up the melting process. While preventive measures like optimal tilt angle and snow guards can help, you may need to install heating elements to combat excessive sediments.

There are three types of heating systems: electrical, hydronic, and PVT. We’ve gathered all the information on their specifics in a big comparison table to help you choose the right system and deal with snow on solar panels.

Parameter Type of heating system
Electrical Hydronic PVT (Photovoltaic Thermal) Panels
Description Heating cables are attached to the back of the solar panel. When activated, these cables generate heat, melting snow. A network of tubes embedded behind the panels circulates a heated fluid to melt snow. These hybrid panels use excess heat generated by the solar cells to melt snow on the panel surface.
  • Simple and effective for small systems
  • More energy-efficient option
  • The most efficient use of solar energy
  • High energy consumption
  • May not suit large-scale systems due to heating costs
  • Complex and expensive to install
  • Requires additional plumbing
  • Far more costly than traditional panels


While choosing the preferable method, consider their cost-effectiveness. In addition, consult with a qualified solar installer familiar with your area’s climate to determine the best solar panels for cold climates.

Get a Free Quote and Tackle the Issue of Snow on Solar Panels

It’s safe to say that cold weather helps panels remain productive. The only time snow noticeably changes system performance is during a snowstorm.

Chicago’s winters are famous for their snowfalls. Once you decide to install solar panels in Illinois, you need to accept the weather’s impact on electricity generation and consider measures to prevent the snow and ice accumulation.

Looking for the right solar system able to endure any weather conditions in Illinois? Get your free solar quote in a matter of minutes!

Frequently Asked Questions

How do solar panels work in the winter?

Solar panels rely on capturing sunlight particles to convert their energy into electricity. Winters have shorter days, so even on the sunniest day, panels generate less electricity than in summer. Fresh snow on solar panels can act as the reflector, while accumulated snow will act as a barrier, blocking sunlight and significantly reducing electricity generation.

Do solar panels work when covered with snow?

Yes, but they generate far less electricity than usual, even if it’s a small solar light. Snow is a physical barrier preventing sunlight from reaching the solar cells. So, panels covered in snow have less efficiency. A light dusting might have little to no impact, while a heavy blanket will significantly block sunlight.

Do solar panels produce less in winter?

Yes, even in sunny weather. Winter days are naturally shorter than summer ones. Your panel will generate 20-30% less than on a summer day with similar cloudiness. Heavy snow hinders power production.

Does snow affect solar panels if it is a snowfall?

Yes, the impact type depends on the amount of the snow. A light dusting may act as the reflector, increasing the system’s productivity. Moderate snowfall slightly reduces the panel’s efficiency. Heavy snowfall can significantly hinder electricity generation.