Lets put down some Swedish numbers.

During the coldest winter month, solar energy produce (as per statistics from the solar industry in Sweden) somewhere around 3-7% of the amount produced during the warmest month. Households also consume around 2-4 times the amount of energy during the coldest month compared to the warmest month. Sweden is a country where only a small minority have air conditioning installed at home.

Those are the worst month vs the best month. Overall the winter is not that bad, but it is still pretty bad for solar. Talking with people who has had solar installed here, the general story is very similar. During periods where it do produce the market price is already exceptional low, so it isn't returning a major saving. When the market price is high, the output is low, forcing them to be connected to the grid and pay whatever the electrical company demand during the highest market peaks, as well as taxes and grid fees which themselves has increased to match the cost of high variability.

All this looks very different in countries with much warmer climates and where the major energy consumption from households are air conditioning.