I think they put the date in the subtitles in a scene at the Rezidentura. It was late January, 1982. It seems like with any actual historical events or how the trees look or how many months have passed, we're just expected to not think about it too hard. The first season supposedly ended in May or April, 1981, yet it's 2 months later and January, 1982. They have to keep moving the timeline forward to get through the cold war and keep up with the kids aging, but it would've been weird if Elizabeth had been gone for 8 months, or if we skipped all the important aftermath of her return.

I just have to keep looking past the beautiful fall foliage. :)