Why is production lower in the winter than in the summer?

Energy Production Throughout the Year

Your system's energy production changes throughout the year, primarily due to weather variations, seasonal changes in the sun's path across the sky, and changes in the number of daylight hours. Bright, clear days produce the most energy, especially if the angle of the sun is optimal and the temperature is cool. Your system generally produces more energy during the summer when the angle of the sun's path is high and there are more hours of daylight.

However, solar systems work more efficiently in lower temperatures so your system can have high energy production on cold, bright days as well. System production can be impacted any time of the year by shading, cloud cover, or soiling (dirt, snow, or other debris on the surface of the solar panels).

If the weather is clear but production is low, there may be dirt, snow, or other debris on the surface of the solar modules. On cloudy or rainy days, your system will produce less energy. The impact of clouds on your system's daily energy production will be based on the type and duration of the cloud cover.