Depends where you live. If you live here, sun wouldn't be up for a few months at a time, so the battery would have to be pretty big. And it can easily drop below -30C for long periods
A very small % of the global population lives in those conditions. We can thus safely ignore it as an edge case for now, and still solve for the vast majority of emissions reduction
https://www.iea.org/data-and-statistics/charts/lcoe-and-valu...
(If not it soon will be.)