By Sudeep S – Electrical Engineer & Solar Expert
One of the most common questions I get as a solar engineer is:
👉 “Do solar panels still work on rainy or cloudy days?”
It’s a valid concern. After all, solar panels depend on the sun to generate power. But here’s the truth: solar panels still work in rainy and cloudy weather—just not at their full capacity. Let’s break it down in simple terms so you know what to expect before investing.
1. How Solar Panels Generate Power
Solar panels convert sunlight into electricity using photovoltaic (PV) cells. These cells don’t need direct, blazing sunlight; they just need light photons, which are present even when the sky is overcast.
This means that even on cloudy or rainy days, panels continue to generate electricity—though at a reduced efficiency.
2. Solar Panel Performance in Cloudy Conditions
- On cloudy days, solar panels typically operate at 10%–30% of their normal capacity.
- For example, if your panels usually generate 30 kWh/day in bright sun, they may still produce 3–9 kWh/day in cloudy weather.
- The exact output depends on cloud density, time of day, and panel quality.
Fun fact: Germany, one of the world’s leaders in solar power, gets fewer sunny days than many U.S. states—yet solar thrives there.
3. Solar Panel Performance in Rainy Weather
Rainy days often bring heavy clouds, so production drops similar to cloudy conditions. However, rain has a hidden benefit:
🌧️ Rain cleans your panels.
Dust, pollen, and dirt can reduce efficiency by up to 5–10%. Rain naturally washes these away, helping your panels work better once the sun is back.
So, while you lose some generation during rain, you gain long-term efficiency through cleaner panels.
4. Seasonal Variations
Solar is designed with year-round averages in mind.
- In summer, you’ll generate more electricity than you need.
- In winter or rainy seasons, you’ll generate less.
- Net metering (where available) lets you send extra summer power to the grid and use credits during lower-production months.
This balances things out so you can rely on solar all year.
5. Do Premium Panels Perform Better in Clouds?
Yes. High-efficiency panels (like SunPower, LG, or REC) perform better in low-light conditions.
They use advanced photovoltaic technology that captures a wider spectrum of light, meaning they can produce 20–30% more energy on cloudy days compared to budget panels.
If you live in a cloudy region (like Seattle, Portland, or the Northeast), premium panels are worth the investment.
6. How to Maximize Solar Performance in Cloudy or Rainy Areas
Here are my expert tips:
✅ Oversize your system – Install a slightly larger system to cover cloudy-day losses.
✅ Choose the right panels – Go for high-efficiency or bifacial panels that capture indirect sunlight.
✅ Add battery storage – Store extra power on sunny days to use during rainy or blackout days.
✅ Regular maintenance – Ensure panels are clean and not shaded by trees.
7. Case Example – A 2000 sq. ft. Home
- Normal sunny output: 30 kWh/day
- Cloudy/rainy output: 6–9 kWh/day
- Annual balance: Despite cloudy days, a properly sized system still meets 70–100% of annual needs.
This is why system sizing is crucial—you want enough panels to offset lower-production days.
8. The Bottom Line
So, will solar panels work in rainy or cloudy weather?
✅ Yes, but at reduced efficiency (10–30%).
✅ Rain actually helps by cleaning panels.
✅ With net metering, battery storage, and the right system size, cloudy or rainy days won’t affect your overall savings.
As someone who has installed residential and commercial solar systems for decades, I can assure you—solar power is still a smart investment, even if you don’t live in a sunny desert.
The key is proper design, high-quality panels, and realistic expectations. Rainy and cloudy days may slow production, but over the 25+ year lifespan of your panels, you’ll still see massive savings and energy independence.
👉 Thinking of going solar? Don’t just look at sunny days—plan for your yearly energy needs. A well-designed solar system will keep your home powered rain or shine.