Do solar panels work in winter?
Yes. Solar panels run on daylight, not warmth, so they keep working on cold, bright days. They make less power in winter because the days are short and the sun is low, so most of your year's power comes from spring to autumn.
Light, not heat
Panels turn daylight into electricity. Cold weather doesn't stop them; in fact panels work slightly more efficiently when they're cool. What matters is how much light reaches them.
Why winter output is lower
In December the sun is low and the days are short, so there's simply less light to work with. A system that does well in June might make a fraction of that in mid-winter. That's normal, and installers account for it when they estimate your yearly output.
Snow and cloud
Panels still generate under cloud, just less. A light dusting of snow usually slides off the glass quickly. Heavy snow will stop them until it clears; you don't need to climb up and brush it off.
Getting more from winter
A battery lets you store what you make in the day for the evening. Some people also charge a battery on a cheap overnight tariff in winter, then use solar to top it up in summer.
Ask your installer
Ask for a month-by-month output estimate for your roof, not just a yearly total. It shows you what to expect in winter and makes quotes easier to compare.