I think a combination of tiny wind + solar + supercapacitors has potential to smooth the bumps out. I’m not in a high wind area, but the average wind speeds are highest during the months solar energy is the lowest.
If whatever is holding the charge can opportunistically harvest a high percentage of solar in short durations, I really only need to get through 7-8 weeks of non-useful solar. 2nd week of November and 1st week of February tend to have decent solar energy for an hour or two (when it’s not cloudy).
Another idea I’ve been tossing around is just dropping off higher capacity (e.g., golf car) lead acid batteries in the fall, and picking them up in the spring to charge. Lead acid doesn’t really freeze unless they’re discharged pretty far, and they’ll still output power when it’s very cold (cars still start at -30F). I haven’t run the numbers, but it might be possible to just run a low-power repeater all winter without drawing the battery below ~12.0V.