I don't know what GP meant about "most places", but I guess generally places that have a winter (away from the tropics, that is) are cloudier in the winter, as

I don't know what GP meant about "most places", but I guess generally places that have a winter (away from the tropics, that is) are cloudier in the winter, as well as by definition having lower solar irradiation. Most of Europe is in the unenviable position of having higher power requirements precisely when solar potential is at the lowest[0]. [0]: https://www.researchgate.net/figure/Typical-winter-and-summer-day-solar-irradiation-and-European-electricity-load-profiles_fig1_215681334 https://www.researchgate.net/figure/Typical-winter-and-summe...