Do solar panels work in snow and cloudy winters?

Panels produce when light reaches the cells. A layer of snow stops that until it sheds or melts. Cloudy winter days produce less than July, even when the glass is clear. Neither fact means the annual total is zero.

Snow

A steep roof sheds faster than a low-tilt or flat roof. Chicago bungalow flats and low-slope Maryland roofs hold snow longer than a steep Grand Rapids or Scranton roof. Lake-effect belts, including Erie, Cleveland, Akron, and the west side of Michigan, get more of it. The production model should show winter months, not only a sunny annual average.

Do not climb a icy roof to clear modules. That is how people get hurt. Most pitched arrays clear on their own.

Clouds

Our statewide figures are about 3.8 peak sun hours in Michigan, 4.0 in Ohio, 4.2 in Illinois, and 4.0 in Pennsylvania. Those are rounded annual resources, not a promise for January. A model that uses a desert weather file will overstate a Detroit or Cleveland year.

Design choices

South-facing and reasonably steep is the simple winter layout. Shade from trees and hills matters more when the sun is low. What size system fits your bill is the usage side. The installer still has to run a weather file for the address.