Do solar panels produce less in winter?
Yes — but less than you'd think. Real numbers by latitude and how to get the most from winter sun.
Yes, panels produce less in winter. But not because of cold (panels actually run more efficiently when cool) — because there are fewer sun hours and the angle is lower. Real numbers below.
Real numbers by latitude (US)
- Phoenix (33°N): June 7.0 PSH, December 4.0 PSH → -43%
- Atlanta (34°N): June 5.7 PSH, December 3.0 PSH → -47%
- New York (41°N): June 5.5 PSH, December 2.5 PSH → -55%
- Seattle (48°N): June 5.0 PSH, December 1.3 PSH → -74%
- Anchorage (61°N): June 5.3 PSH, December 0.5 PSH → -91%
Why your home produces 30-50% less in winter
Three factors combine: sun lower (more atmosphere, less energy), shorter days (fewer production hours), and more cloud cover. The good news: cold panels actually run 2-4% more efficiently than hot summer ones.
How to optimise for winter
- Higher tilt (45-55° instead of 30-35°): captures low winter sun head-on
- No shading: low winter sun means trees, buildings and hills cast longer shadows
- Clear snow when needed (snow blocks 100% of output)
- Run controllable loads (water heater, EV) at solar noon
What quotes don't tell you
Most quotes show annual estimated output. Look at the monthly breakdown: in December you may be producing only 35-50% of your consumption. The grid covers most of it in January-February. That's normal.
To optimise see optimal orientation and tilt, and for snow impact, solar panels in rain and snow.
Want to know how much energy your appliances use? Calculate it here.
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