Solar Generation On Cloudy Days

Solar power is quickly emerging as an alternative competitor to energy generated from fossil fuels, but how much energy can a solar panels generate on cloudy days? Industry experts say that a typical home solar system will produce approximately 30% of its maximum capacity on a days that the sun may shine for only half of what is typically expected. However, a more accurate measurement of your system’s potential may vary depending on your geographic region.

Solar Generation by Region & Climate

Regional differences in sunlight, elevation, climate and precipitation can explain much of the variability in solar energy potential across Canada. For example, regions like British Columbia have greater energy generation potential due to the angle of the sun. In fact, homeowners in this region generate more electricity power than any region west of Quebec.

In Toronto, by contrast, solar power output is lower. Here, the angle of the sun at noon (around the time that solar generation peaks) is less than in British Columbia, and cloud cover—which can reduce light levels even further—is common during the summer months.

Moreover, in parts of Canada where snowfall occurs regularly (e.g. Alberta), solar panels are better suited for roof installation in order to maximize the sunlight that can be captured by a typical solar panel system. This can result in a lower rate of effective energy production as snow accumulation or melting during winter months may affect the system’s ability to capture sunlight as light may not always reach solar panels directly.

In some areas, weather patterns can also vary considerably. The amount of daylight hours for solar generation in a particular area is very much dependent on cloud cover, snowfall, and other factors—some of which can be offset by investing in higher-quality panels that have been engineered to capture sunlight more effectively.

How Do Clouds Affect Solar Panel Energy Generation?

The short answer is that it depends on the type of solar panels used. Newer generations of solar panels use diffraction to pull in more energy from sunlight that would normally be blocked by clouds or spread out over a wide area. These newer panels can often produce just as much electricity behind a cloud as they would with no clouds at all.

Diffused Sunlight

Direct sunlight that reaches a solar panel can cause energy levels to rise quickly. This enables more current to flow through the circuit and create a build-up of power. With diffused light, however, efficiency issues may arise as this light does not generate as much power as direct sunlight. Low levels of light over long periods can build up similar power output, however, process takes more time. If there are large clouds temporarily blocking the sun, the diffused light that seeps through the cloud cover will result in longer charging times. Despite its potential drawbacks, diffused sunlight does have its advantages over direct sunlight. Energy from diffused sunlight is spread out over a larger area when compared to direct sunlight which assists with panel efficiency. Also, as diffused sunlight can result in circuitry that charges more slowly than direct sunlight, there is less current running through the available circuits.

New Technology & Cloud Cover

Newer generations of solar panels have lattice structures that allow them to catch more energy from diffused light. These lattice structures use prisms to bend the light at approximately a 45 ° and refocus the light on the available solar panels. The combination of diffused light and new technology enables newer panels to generate electricity despite any cloud cover. This new and improved efficiency makes them an ideal fit for remote locations since they no longer require direct sunlight for power generation in order for the homeowner’s investment in a solar panel system to be worthwhile.

Long-Term Cloud Cover

Although clouds typically move throughout the day, occasionally, clouds can maintain their position resulting in diffused light for a prolonged amount of time. This typically is only the case for remote areas tend to affect your solar panel system’s ability to generate energy. Although these situations are less common, they do occur and can result in less sunlight capture on an annual or seasonal basis. Some homeowners in remote areas may elect to install large mirrors to reflect light toward your solar panel system.

Redirecting sunlight can be just as useful and efficient as diffused light that may shine through clouds. With these arrangements, homeowners located in remote areas may be able to construct custom solutions that can help justify the investment costs associated with a solar panel system.


Although cloud cover can affect a solar panel system, clouds are not the obstacle that they used to be. Technology advancements have resulted in newer solar panel systems that can still use diffused sunlight to produce consistent energy for your household. Canadians from coast to coast are blessed with an abundance of natural sunlight that persists for a majority of the year, even through the winter season. Although there are a few drawbacks, clouds provide plenty of benefits including the reflection of natural sunlight back to the surface of the earth. This results in a plethora of geographic regions that can receive sunlight and generate energy despite the cover of clouds.