Understanding Seasonal Solar Production Changes
If your solar system was cranking out power all summer and suddenly looks lazy in the fall and winter, that doesn't mean anything is wrong. Solar production always dips in the colder months due to changes in the sun's position and available daylight.
Here's what affects your winter production:
Shorter Days = Less Sunlight
As we move into fall and winter, the number of daylight hours decreases. With fewer hours of direct sun, your system simply has less time in the day to generate energy. Even perfectly functioning systems will show a drop.
The Sun Sits Lower in the Sky
During winter--especially around the winter solstice (December 21) -- the sun travels a lower arc. This reduces the intensity and angle of sunlight hitting your panels. Even on clear days, this naturally lowers production.
Winter Weather Conditions
Clouds, storms, and snow can all temporarily reduce exposure to sunlight. Even light cloud cover can noticeable impact output.
How PlugPV Designs Your System for This
We use PVWatts modeling when designing your system to intentionally account for these seasonal dips. That means:
Your system is sized to over-produce in the summer
That extra summer production helps balance out the lower winter months
Annual production targets (not monthly,) drive system design
So a winter dip isn't a malfunction -- it's expected behavior.
If Your Offset is Below 100%
Customers with systems designed for less than full annual offset may see their electric bill increase more noticeably during the winter. This doesn't indicate a problem; it simply reflects seasonal imbalance between solar generation and household consumption.
When to Reach Out
If you notice an unexpected or sudden drop that doesn't align with normal seasonal trends -- for example, a sharp decline on a sunny day or production falling to zero -- feel free to reach out. We're always happy to check your system for issues.