Do solar panels work in winter? Yes — and snow even washes them
Answer-first page — the first paragraph is the whole answer, checked reviewed 2026-08-08
Yes: panels produce in winter. Cold actually makes them slightly more efficient — the winter drop is about shorter days and lower sun height, not temperature. Snow slides off tilted arrays as soon as a few hours of sun hit them; the December-vs-July gap is your state's seasonal curve.
The seasonal numbers
Sun data (Open-Meteo 2024, capital average): e.g. Arizona July ~7.0 vs Dec ~3.9 kWh/m²/day; Washington State July ~6.4 vs Dec ~0.6 (winter real!). That's why the seasonal shape is the biggest variable in your state's worth-it math.
If winter is the margin: over-size for December, keep the net credits from summer, or add a battery to move the sunny season into winter hours. The sun curve page shows the season shape for all 50.