Solar panels still generate electricity on cloudy days and in cold weather, albeit less.

Clouds cut output as less sunlight reaches the panels, but they continue producing power from indirect light. Snow cover can temporarily block light, though it is typically not obstructed by thin layers of snow. Additionally, most solar panels in the U.S. run more efficiently in cooler weather, as heat lowers performance.

Winter generation can be lower due to shorter days, notably at middle latitudes; cities like Denver receive nearly three times more solar energy in June than December. This mainly affects what share of a home’s electricity solar covers, especially where heating raises demand. Average winter electricity use of U.S. homes is estimated to be six times that of summer use. 

Despite seasonal dips, solar still displaces fossil fuel electricity over the year, delivering large net emissions reductions across a panel’s multi-decade lifespan.

See a full discussion of this at Gigafact.org

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Sources

• Renewable Energy Journal On the investigation of photovoltaic output power reduction due to dust accumulation and weather conditions
• Renewable Energy Journal Temperature and thermal annealing effects on different photovoltaic technologies
• ACS Omega Journal Comprehensive Analysis of Solar Panel Performance and Correlations with Meteorological ParametersC
• SEIA What happens to solar panels when it’s cloudy or raining?
• US Department of Energy Solar Photovoltaics Supply Chain Deep Dive Assessment
• US Department of Energy Let it Snow: How Solar Panels Can Thrive in Winter Weather
• Columbia Law School Sabin Center for Climate Change Law Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles

This fact brief was originally published by Skeptical Science on February 19, 2026, and was authored by Sue Bin Park. Skeptical Science is a member of the Gigafact network.

Solar panels produce far less emissions than coal or natural gas.

“Lifecycle emissions” counts all aspects of raw materials, manufacturing, transport, installation, operation, and disposal. A major National Renewable Energy Laboratory review of thousands of studies found that while some emissions are generated when solar panels are manufactured and shipped, their lifetime emissions are much lower than fossil fuels. Coal’s lifecycle climate pollution is about 23 times higher than solar power, and natural gas about 11 times higher.

Solar panels also “pay back” their upfront emissions within a few years of operation, offsetting emissions from their manufacture. Since modern panels often last 30 years or more, they will continue to provide decades of low-emissions electricity after their payback.

See a full discussion of this at Gigafact.org

This fact brief is responsive to conversations such as this one.

Sources

• National Renewable Energy Laboratory Life Cycle Greenhouse Gas Emissions from Electricity Generation: Update
• IPCC Technology-specific Cost and Performance Parameters
• US Department of Energy End-of-Life Management for Solar Photovoltaics
• International Journal of Advanced Research in Science, Communication and Technology Solar Panel Heat Emission and its Environmental Impact
• Columbia Law School Sabin Center for Climate Change Law Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles

This fact brief was originally published by Skeptical Science on January 17, 2026, and was authored by Sue Bin Park. Skeptical Science is a member of the Gigafact network.

Toxic heavy metals in solar panels are locked in stable compounds and sealed behind tough glass, preventing escape into air, water, or soil at harmful levels.

Most concern focuses on cadmium and lead. 40% of new U.S. panels use cadmium telluride, which does not dissolve in water, easily turn to gas, or approach the toxicity of pure cadmium.

Like many electronics, panels contain small amounts of lead. These parts are locked behind tempered glass that resists hail, heat, and breakage. Even in high-temperature fires, the glass melts and binds to the metals, trapping 99.9% of them.

During manufacturing and disposal, heavy metals are handled under safety and waste rules. Per unit of electricity, solar releases far less heavy metals than fossil fuels.

Studies and safety reviews find that heavy metals pose no qualifiable danger to health during the regular manufacture, use, or regulated disposal of solar panels.

See a full discussion of this at Gigafact.org

This fact brief is responsive to conversations such as this one.

Sources

• NREL Polycrystalline Thin-Film Research: Cadmium Telluride
• NC Clean Energy Technology Center Health and Safety Impacts of Solar Photovoltaics
• American Chemical Society Emissions from Photovoltaic Life Cycles
• EPA Solar Panel Frequent Questions
• Massachusetts Department of Energy Resources Questions & Answers: Ground-Mounted Solar Photovoltaic Systems
• EPA Ecological Soil Screening Level
• Columbia Law School Sabin Center for Climate Change Law Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles

This fact brief was originally published by Skeptical Science on December 14, 2025, and was authored by Sue Bin Park. Skeptical Science is a member of the Gigafact network.

The planet continues to warm due to human activity; bouts of cold weather don’t change this. 

Satellites around the world measure temperatures at different places throughout the year. These are averaged to calculate annual global temperatures. 

The past ten years (2015-2024) have been the ten hottest since modern record-keeping began in 1850, and 2024 was the all-time hottest. The last time Earth had a colder-than-average year was 1976. 

Weather refers to meteorological conditions —  heat, humidity, precipitation, etc. — in a given moment, while climate represents patterns of weather over time.

Cold snaps still occur, but they’re becoming less common as Earth warms from human emissions of heat-trapping gases.

See a full discussion of this at Gigafact.org

This fact brief is responsive to conversations such as this one.

Sources

• NOAA 2024 was the world’s warmest year on record
• Scientific American The Past Three Summers Were the Three Hottest on Record
• Yale Climate Connections September 2025: Earth’s 3rd-warmest September on record
• NOAA Global Climate Report August 2025
• Carbon Brief State of the climate: 2025 on track to be second or third warmest year on record

This fact brief was originally published by Skeptical Science on November 2, 2025, and was authored by Sue Bin Park. Skeptical Science is a member of the Gigafact network.

Wisconsin Watch partners with Gigafact to produce fact briefs — bite-sized fact checks of trending claims. Read our methodology to learn how we check claims.