Path-Q Solar
How does frequent cloudy weather affect the production estimate for rooftop solar?
Answer
Clouds reduce solar irradiance and therefore reduce output, sometimes sharply during heavily overcast periods, but panels still produce some energy from diffuse light. A reliable estimate should use location-specific weather data and account for seasonal cloud patterns rather than applying a generic cloud-loss percentage.
Key points
- Thin, broken clouds usually reduce output less than dense overcast conditions.
- Cloud effects vary by season, weather year, roof orientation, and the model's weather dataset.
- Cloudy weather changes both daily production and the amount of battery or grid energy needed.
What it depends on
- Local climate and weather dataset
- Array orientation, tilt, and shading
- System size and household or business load timing
- Battery and export arrangements
Risks and trade-offs
- Using unusually sunny or unusually cloudy historical periods can distort expectations.
- A system can meet an annual estimate while still producing too little during particular winter or cloudy periods.
- Battery sizing based only on average production may not cover prolonged cloudy conditions.
Information you may need
- Site-specific monthly production estimate
- Weather assumptions and uncertainty range
- Historical load by month or time of day
- Backup requirements and export rules
Your next step
What to do next
Ask the installer to show modeled production for cloudy-season months and the weather data and loss assumptions behind the estimate.
Path-Q
Find the right next step
Answer a few questions and we’ll narrow your options.
Loading…
SQ00526