The phrase “solar only works when it’s sunny” sounds reasonable enough — until you look at the data. It’s one of those ideas that feels true because it fits our intuition, not because it reflects the world.
When most people picture solar power, they imagine a bright, cloudless desert sky: Phoenix, maybe, or Nevada. But that image is misleading. Solar panels generate electricity from light, not heat, and light still reaches the Earth — and your rooftop — even on cloudy or snowy days.
In fact, some of the countries leading the world in solar generation are anything but sunny paradises. Germany, famous for its overcast winters, and Canada, where snow often covers the ground half the year, both show how solar can thrive under grey skies.
Solar photovoltaic (PV) panels convert photons — the particles of light — into electricity. They don’t rely on heat, and in fact, excessive heat can reduce their efficiency. On clear days, panels produce their maximum output. But even on overcast days, enough light filters through the clouds for panels to continue generating power — typically 10–25% of their rated output on heavily cloudy days, and up to 80% on light cloud cover.
That’s because clouds scatter sunlight, but they don’t erase it. It’s called diffuse irradiance — the sunlight that reaches the ground after bouncing through the atmosphere. Your eyes adjust automatically to cloudy light; solar panels just quietly turn it into electricity.
And in cold climates? Panels actually work better. Like most electronics, solar cells lose efficiency when they overheat. Cooler air improves voltage performance, meaning a cold, bright February afternoon in Toronto or Berlin can yield excellent energy output.
If you ever needed proof that solar doesn’t require endless sunshine, look north.
Germany, with less annual sunlight than nearly every U.S. state, has been a solar powerhouse for decades. As of 2024, the country had over 104 gigawatts (GW) of installed PV capacity, generating roughly 74 terawatt-hours (TWh) annually — about 15% of its total electricity production (Clean Energy Wire, 2025). That’s a global benchmark achieved under skies more often grey than blue.
Now consider Canada. It’s known for cold winters, long nights, and short summers — not exactly what you’d think of as solar country. Yet solar is growing rapidly. Ontario alone has installed more than 3.3 GW of solar capacity, and Alberta — historically fossil-fuel dominated — has become one of North America’s fastest-growing solar markets. By early 2025, Alberta’s solar capacity surpassed 2.5 GW, enough to power hundreds of thousands of homes (Natural Resources Canada, 2025).
What both Germany and Canada prove is that solar’s viability depends less on how much sunshine a region gets, and more on policy, infrastructure, and public investment. Cloud cover is a factor — but it’s not a limit.
So if the data is clear, why does the myth hang on?
Partly because it feels intuitive, and partly because of how we tell the story of solar power.
Changing this perception requires more than technical corrections — it means reshaping how we talk about solar power.
If you look at where solar has grown fastest, it’s not just in the world’s sunniest regions. It’s where policy met persistence — where governments and communities treated solar not as a fair-weather friend but as a dependable, evolving technology.
The myth that “solar only works when it’s sunny” is, at its core, a failure of imagination. We’ve been taught to see clean energy as something fragile — easily dimmed by clouds. But the evidence says otherwise. Solar panels hum along through drizzle, sleet, and fog. They don’t need perfection; they just need light.
And as Germany and Canada both prove, even under cloudy skies, the light is enough.