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Polar bear family and cubs from arctic village Kaktovik in Alaska. Piriya Photography / Getty Images

By Jessica Corbett

A coalition of conservation groups sued the Biden administration on Thursday over the U.S. Department of the Interior's recent rule allowing fossil fuel companies to harass polar bears and walruses while searching and drilling for oil and gas in the Southern Beaufort Sea.

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The view from photographer´s house of the wildfire of Sierra Bermeja taking place in Andalucia on September 13, 2021 in Estepona, Spain. Bianca de Vilar / Getty Images

By Andrea Germanos

A new analysis reveals a near total global failure of governments to have climate action and targets on track for limiting global warming to 1.5 degrees Celsius above pre-industrial levels.

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MAXSHOT / iStock / Getty Images

Solar panels allow you to harness the sun's clean, renewable energy, potentially cutting your electric bills as well as your environmental footprint. But do solar panels work on cloudy days, or during seasons of less-than-optimal sun exposure? For homeowners who live outside of the Sun Belt, this is a critical question to consider before moving ahead with solar panel installation.

In this article, we'll go over how solar panels work on cloudy days, whether solar panels work at night, and how to ensure you always have accessible power — even when your panels aren't producing solar energy.

How Solar Panels Work on Cloudy Days

Photovoltaic (PV) solar panels can use both direct and indirect sunlight to generate electrical power. This means they can still be productive even when there is cloud coverage. With that said, solar panels are most efficient and productive when they are soaking up direct sunlight on sunny days.

While solar panels still work even when the light is reflected or partially obstructed by clouds, their energy production capacity will be diminished. On average, solar panels will generate 10 to 25% of their normal power output on days with heavy cloud coverage.

With clouds usually comes rain, and here's a fact that might surprise you: Rain actually helps solar panels work more effectively. That's because rain washes away any dirt or dust that has gathered on your panels so that they can more efficiently absorb sunlight.

Do Solar Panels Work at Night?

While solar panels can still function on cloudy days, they cannot work at night. The reason for this is simple: Solar panels work because of a scientific principle called the photovoltaic effect, wherein solar cells are activated by sunlight, generating electrical current. Without light, the photovoltaic effect cannot be triggered, and no electric power can be generated.

One way to tell if your panels are still producing energy is to look at public lights. As a general rule of thumb, if street lamps or other lights are turned off — whether on cloudy days or in the evening — your solar panels will be producing energy. If they're illuminated, it's likely too dark out for your solar panel system to work.

Storing Solar Energy to Use on Cloudy Days and at Night

During hours of peak sunlight, your solar panels may actually generate more power than you need. This surplus power can be used to provide extra electricity on cloudy days or at night.

But how do you store this energy for future use? There are a couple of options to consider:

You can store surplus energy in a solar battery.

When you add a solar battery to your residential solar installation, any excess electricity can be collected and used during hours of suboptimal sun exposure, including nighttime hours and during exceptionally cloudy weather.

Batteries may allow you to run your solar PV system all day long, though there are some drawbacks of battery storage to be aware of:

  • It's one more thing you need to install.
  • It adds to the total cost of your solar system.
  • Batteries will take up a bit of space.
  • You will likely need multiple batteries if you want electricity for more than a handful of hours. For example, Tesla solar installations require two Powerwall batteries if your system is over 13 kilowatts.

You can use a net metering program.

Net metering programs enable you to transmit any excess power your system produces into your municipal electric grid, receiving credits from your utility company. Those credits can be cashed in to offset any electrical costs you incur on overcast days or at night when you cannot power your home with solar energy alone.

Net metering can ultimately be a cost-effective option and can significantly lower your electricity bills, but there are a few drawbacks to consider, including:

  • You may not always break even.
  • In some cases, you may still owe some money to your utility provider.
  • Net metering programs are not offered in all areas and by all utility companies.

Is Residential Solar Right for You?

Now that you know solar panels can work even when the sun isn't directly shining and that there are ways to store your energy for times your panels aren't producing electricity, you may be more interested in installing your own system.

You can get started with a free, no-obligation quote from a top solar company in your area by filling out the 30-second form below.

FAQ: Do Solar Panels Work on Cloudy Days?

How efficient are solar panels on cloudy days?

It depends on the panels, but as a rule of thumb, you can expect your solar panels to work at 10 to 25% efficiency on cloudy days.

How do solar panels work when there is no sun?

If there is literally no sunlight (e.g., at night), then solar panels do not work. This is because the photovoltaic effect, which is the process through which panels convert sunlight into energy, requires there to be some light available to convert.

However, you can potentially use surplus solar power that you've stored in a battery. Also note that solar panels can work with indirect light, meaning they can function even when the sun is obscured by cloud coverage.

Do solar panels work on snowy days?

If there is cloud coverage and diminished sunlight, then solar panels will not work at their maximum efficiency level on snowy days. With that said, the snow itself is usually not a problem, particularly because a dusting of snow is easily whisked away by the wind.

Snow will only impede your solar panels if the snowfall is so extreme that the panels become completely buried, or if the weight of the snow compromises the integrity of your solar panel structures.

Will my solar panels generate electricity during cloudy, rainy or snowy days?

Cloudy days may limit your solar panel's efficiency, but you'll still be able to generate some electricity. Rainy days can actually help clean your panels, making them even more effective. And snowy days are only a problem if the snow is so extreme that the panels are totally submerged, without any part of them exposed to the sun.

A calf of the Holstein-Friesian breed on a dairy farm in Germany. Sebastian Willnow / picture alliance via Getty Images

By Brett Wilkins

Global food production accounts for more than a third of all greenhouse gas emissions, with meat and dairy responsible for twice as much planet-heating carbon pollution as plant-based foods, according to the results of a major study published Monday.

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A pair of fish swim near the ocean floor off the coast of Mauritius. A motion calling for an end to deep sea mining of minerals was adopted at the world congress of the International Union for the Conservation of Nature this week. Roman Furrer / Flickr

By Julia Conley

A vote overwhelmingly in favor of placing a moratorium on deep-sea mineral mining at a global biodiversity summit this week has put urgent pressure on the International Seabed Authority to strictly regulate the practice.

The vast majority of governments, NGOs, and civil society groups voted in favor of the moratorium at the world congress of the International Union for the Conservation of Nature (IUCN) on Wednesday, after several conservation groups lobbied in favor of the measure.

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EPA Moves to Protect Alaska's Bristol Bay, Blocking Major Gold Mine

"Today we celebrate. Tomorrow, we get back to the hard work of seeing this through."

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Protestors gathered in Dillingham, Alaska, for a rally against the Pebble Mine on June 6, 2007. Luis Sinco / Los Angeles Times / Getty Images

By Jessica Corbett

Conservationists, local tribes, and commercial fishers celebrated on Thursday the Biden administration's move to permanently protect Alaska's Bristol Bay watershed from the proposed Pebble Mine and similarly destructive projects.

"Placing a massive mine at the headwaters of the world's greatest, most productive wild sockeye salmon fishery has been a terrible idea from the start," said Kristen Miller, acting executive director of Alaska Wilderness League, "and today's administrative decision and its commitment to following science and protecting clean water is directly attributable to the decadeslong, tribal-led effort to protect Bristol Bay."

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Doctors join Extinction Rebellion activists in Trafalgar Square on Oct. 12, 2019 in London, England. Chris J Ratcliffe / Getty Images

By Brett Wilkins

Asserting that humanity "cannot wait for the pandemic to pass" before acting to rapidly reduce carbon emissions fueling the climate emergency, more than 220 health journals around the world on Sunday published an unprecedented joint editorial calling for "urgent action to keep average global temperature increases below 1.5°C, halt the destruction of nature, and protect health."

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Photos captured by National Oceanic and Atmospheric Administration aircraft August 31, 2021 and reviewed by the Associated Press show a miles-long black slick floating in the Gulf of Mexico near a large rig. NOAA via AP

By Jessica Corbett

As Louisiana residents and officials begin the recovery process in the wake of Hurricane Ida, environmental campaigners responded Thursday to reporting of a suspected oil spill in the Gulf of Mexico by saying such scenes "are reminders that when we drill, we spill."

"On top of the devastation that people are still experiencing onshore, we are now learning about an oil slick in the Gulf, not far from the Louisiana coast," said Kelsey Lamp, Protect our Oceans campaign director with Environment America, in a statement.

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A woman prepares cuttings for reforestation near Oumé, in southwestern Ivory Coast — a region affected by deforestation due to cocao cultivation — on May 19, 2021. Issouf Sanogo / AFP via Getty Images

By Brett Wilkins

Nearly a third of the world's tree species are at risk of extinction largely due to agriculture, logging, and, increasingly, the global climate emergency, according to a report published Wednesday by a UK-based conservation group.

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Patrick Goguen, right, an Acadian from Moncton, beats on a drum on Canada's Miscou Island while Noel Milliea, an elder from Elsipogtog First Nation, performs a ceremony on a dead right whale known as Wolverine to honor the animal's spirit before a necropsy on June 7, 2019. Nathan Klima for The Boston Globe via Getty Images

By Jessica Corbett

Conservation advocacy groups on Tuesday responded with alarm and disappointment to the Biden administration's long-awaited new rule for protecting the endangered North Atlantic right whales from Maine to Florida.

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'Ban Neonicotinoids Right Now,' Say Conservationists After EPA Pesticide Review

"The EPA doesn't need any more proof," said one expert after agency analyses detailed threat to endangered species.

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A honey bee approaches a painted lady butterfly perched on a flower in a North Tustin garden on March 13, 2019, as swarms of butterflies invade Southern California as a result of an unusually heavy migration making its way from Mexico to the Pacific Northwest to breed, experts say. Mark Rightmire / MediaNews Group / Orange County Register via Getty Images

By Andrea Germanos

Environmental and food safety advocates highlighted Thursday the decline in iconic pollinators following new analyses released by the U.S. Environmental Protection Agency showing three widely used neonicotinoid insecticides are "likely to adversely affect" the majority of the endangered plants and animals the agency assessed.

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Atmospheric CO2 Levels Haven't Been This High in 800,000 Years: NOAA

A major report on climate says both greenhouse gas concentrations and global sea levels hit record highs in 2020.

Climate
An evacuated resident points in the direction of his home following a flash flood, which came as Tropical Storm Henri made landfall, in Helmetta, New Jersey on August 22, 2021. Tom Brenner / AFP / Getty Images

By Kenny Stancil

Bolstering the case for meaningful climate action, a major report released Wednesday found that Earth's atmospheric greenhouse gas concentrations and sea levels both hit record highs in 2020.

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Demonstrators protest the Line 3 pipeline on the grounds of the Minnesota State Capitol on Aug. 25, 2021. RootsAction

By Jake Johnson

With Enbridge on the verge of completing its multibillion-dollar Line 3 pipeline, thousands of Indigenous leaders and environmentalists brought their protests against the sprawling tar sands project to the grounds of the Minnesota state capitol building on Wednesday to demand that lawmakers intervene before the dirty oil starts flowing.

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