For starters, you get less sunlight than I do in the south -- less solar energy to convert into electricity. I get 4 peak sun hours per day. https://www.solarreviews.com/blog/peak-sun-hours-explained
Another factor is, I read that the rated wattage from your panels increase by 5 to 10% when they get below freezing. I'm not sure how accurate that is.
Another thing is you do most of your power consumption in the evening in the winter when it's cold, even with a boiler (at least I imagine you do). That means you need power most when there's less sun, compared to me needing power most when there's tons of sun (during hot summer days to run the A/C when the sun's up for many hours). So backup battery power is more crucial for you than me.
Very helpful link, even had a graph of peak hours for Chicago.
We are in DuPage County, due west and entirely TOO CLOSE to Chicago.
Yes, the evening is when the load goes up.
Most of the daytime load is the coffee maker in the AM and the refrigerator on and off.
And the numerous GFI receptacles sucking down ~2 watts each!