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Do Solar Panels Still Work on Cloudy Days?
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Do solar panels produce energy on cloudy days?
Yes, solar panels can still generate electricity even on cloudy and rainy days. The key reason is that solar cells can absorb both direct and diffuse sunlight.
Direct sunlight is the unobstructed beams that shine down when the sky is clear. Diffuse sunlight is sunlight that has been scattered in the atmosphere by clouds, haze, dust, etc.
On overcast days, solar panels are still exposed to ambient diffuse light. While less intense than direct sunlight, this diffuse light can still excite electrons in the solar cells and produce an electrical current.
So don’t believe the myth that solar panels are useless on cloudy days. While they produce less power compared to the full sun, they can still generate electricity from that diffuse light.
How much do clouds impact solar panel efficiency?
The amount of solar electricity you can expect your home to generate during a cloudy day will vary due to:
Thickness of cloud cover - Thinner, higher clouds allow more light through compared to thick, low-lying storm clouds
Type of cloud - High-wispy cirrus clouds permit more sunlight than dense cumulus clouds. Stratus clouds fall somewhere in between
Time of year - More daylight hours in summer vs. winter means more total energy production
Geographic location - Southern regions of the country receive more annual sunlight than northern areas
Local weather patterns - Some areas simply have more overcast days than others
Understanding these factors can give you realistic expectations for solar output. But keep in mind that if you choose to go solar with an experienced partner like Sunrun, you’ll be sure to get a solar system that can accommodate your energy needs even with varying weather factored in.
That said, here are some typical relative solar power outputs based on sky conditions (approximate):
Clear, sunny day - near peak output
Partly cloudy day - 50-80% of peak output
Heavily overcast day - 10-30% of peak output
Relative output ranges are based on solar irradiance data published by the National Solar Radiation Database (NREL / DOE). Actual production varies by system design and location.
Common myths about solar panels on cloudy days
Let’s clear up some common misconceptions about solar and cloudy weather:
Myth: Solar panels don’t work at all on cloudy days.
Fact: Solar panels still generate electricity from diffuse light on overcast and rainy days, just at reduced efficiency.
Myth: Cloudy weather makes solar power unreliable.
Fact: Advanced forecasting and grid integration techniques help balance solar supply and demand, even on cloudy days.
Myth: Solar only works well in the sunniest locations.
Fact: Modern solar panels can still provide clean energy and savings in locations with average sunlight levels. Proper solar panel orientation and tilt help maximize production.
The truth is that most locations receive enough annual sunlight for solar panels to be worthwhile.
To make sure your solar setup can handle the ups and downs of your local weather and keep your energy needs covered, teaming up with a trusted solar provider like Sunrun is a smart move. We’ll craft a personalized system and offer 24/7 system monitoring for total peace of mind.
Do solar panels work at night?
Solar panels require sunlight to function. At night when it’s dark, solar cells stop generating electricity. So how can solar power your home around the clock?
The answer is solar battery storage. By storing excess solar electricity produced during the daytime, batteries can discharge power at night to keep your lights on after sunset.
Batteries also provide backup power during prolonged overcast periods and weather emergencies. Adding battery storage provides true energy independence and resilience.
Solar battery storage systems capture extra solar electricity produced during sunny weather and save it for later use.
With sufficient battery storage, your solar system can keep the lights on and appliances running even when the panels aren’t actively producing power.
Should you go solar if you’re in a cloudy climate?
If you live in an area with lots of rainy and overcast days, you may be wondering if solar power is still a smart investment.
The answer is often yes—with the right solar system design, even cloudy locations can benefit from solar energy.
Here are a few tips to maximize solar production in low-sunlight areas:
Add solar battery storage to save surplus power for cloudy periods
In some lower-sunlight regions, system designs may account for seasonal variability by adjusting panel count, orientation, or efficiency—based on local conditions and utility rules.
Add more panels on north-facing roofs to capture diffuse light
Use high-efficiency panel models with higher wattage
Install east/west facing panels to catch morning and afternoon sun
No matter where you live, there are ways to optimize solar generation. Get a quote with Sunrun to understand how much you could save by going solar.
When do solar panels produce the most energy?
Solar panels work whenever sunlight is available but produce the most electricity during peak sun hours:
Spring - Longer days and more direct sunlight after winter
Summer - Maximum daylight hours around the solstice
Fall - Still fairly long days before winter
Winter - Shortest days but solar output boosted by reflective snow
The most power is generated when the sun is high overhead. Solar production peaks in the late morning and early afternoon.
South-facing panels tilted at an optimal angle receive the most direct sun exposure. But even on cloudy days, ambient and reflected light keeps solar panels generating energy.
Bottom line: When does solar work best?
While solar efficiency may drop on cloudy days, panels can still generate meaningful amounts of electricity from diffuse ambient light.
With proper system sizing and orientation, solar power can be a smart investment even in overcast climates.
Your solar panels will produce the most energy during peak daylight hours with direct sun exposure, but they can still offset a significant portion of your electricity usage on cloudy days. And adding solar batteries to your installation ensures you’ll have power even during unexpected weather conditions.
Consider switching to solar
Don’t let your local weather be a dealbreaker. Our expert Solar Advisors guide you through the complexities and details of solar—from understanding your energy bills, to installation and more. And each Sunrun solar system is custom-designed to fit your home’s unique needs so you can harness the power of the sun, rain or shine.
As the nation's largest home solar & battery installer, we provide dedicated support from initial system design to powering on your system. Our personalized approach ensures that you make the right decisions for your home solar system.
FAQs
Do solar panels still work on cloudy days?
Yes. Solar panels can generate electricity on cloudy and overcast days because they capture diffuse sunlight (light scattered through clouds). Although output is reduced compared to direct sun, panels typically still produce meaningful power when skies are gray.
How much electricity do panels produce on heavily cloudy days?
Solar production drops under heavy cloud cover, but panels can still generate power from diffuse sunlight. Actual output varies widely based on cloud density, panel technology, and system design, and may represent a portion of what the system produces under clear skies.
Do solar panels work at night?
Solar panels do not generate electricity at night because they rely on sunlight. However, solar systems paired with battery storage can use energy produced during the day to power a home after sunset.
Does weather affect solar panel performance?
Yes. Weather conditions such as cloud cover, rain, snow, and airborne particles influence how much sunlight reaches solar panels. Even so, photovoltaic systems can continue producing electricity in many conditions because they respond to available ambient light. System design helps account for seasonal and regional weather patterns.
Is solar still worth it in cloudy climates?
In many cases, yes. Even regions with frequent cloud cover receive sufficient annual sunlight for solar to contribute meaningfully to household energy needs. System sizing, panel efficiency, and energy storage options all play a role in determining long-term value.
Sources
U.S. Department of Energy: Solar integration, radiation & weather impacts on PV systems
NREL: National Solar Radiation Database (NSRDB), current solar irradiance dataset