One example of a binary system is α Centauri. The 80 years orbital period straight inside your range of 70-100 years.
At some point I figured out: if a planet of one of them orbits near the orbital plane of α Centauri AB, within a few degrees of it (likely, all solar system planets orbit inside 7 degrees of invariable plane and half of us inside 1,1 degrees) and the planet then rotates at a moderate axial tilt (also likely, half of us are between 23 and 29 degrees), then while the local sun, in a polar area, rises and sets over the period of local year in polar nights and days... but the other star rises and sets over its orbital period of 80 years.
α Centauri AB´s orbit is also eccentric. Depending on the specific orientation of the axis of planet relative to the apside line of AB orbit, it would be possible for a pole of α Centauri planet to see the other star uninterruptedly as circumpolar star for 65 (Earth) years near apoapse and then not see it for 15 years near periapse. In which case the other pole sees the other star just for 15 years. Or depending on the axis orientation, both poles might see the other star for 40 years, one pole while approaching and the other pole while receding.
Since α Centauri A is brighter than Sun, an Earth-like planet orbiting α Centauri A would have to be further from α Centauri A than Earth from Sun and have longer year. By an obvious estimate, about 16 months.
So a centaur living on a pole could very well enjoy a period of 65 Earth years with winters (about 50 of them) but no night of any kind because α Centauri B never sets and always gives bright light. And then a period of about 15 Earth years when the winters (8 month long, 11 of them) are deep polar nights besides being cold). How would the centaurs adapt to not needing to deal with darkness 65 years at a time?
As for cold itself, that varies. Even now in Holocene, a polar night in Norway coast is as dark (darker when cloudy) but very much warmer than same latitudes in Siberia, Nunavut or Antarctica. Back in Eocene and Cretaceous, the whole Arctic and Antarctic must have been as dark in polar night as now, but were wooded, and with lush forests - apparently no snow cover at polar night! So you can decide how much meridional heat transport you are providing, within a vast range.