In the year after Sakumo's death, Minato is reminded of autumn falling quietly into winter. They visit the northern forests of the country in the last weeks of November; for training he tells Kakashi, but it's really because he sees how heavy the village air is to him.
But not here, because the air is crisp and dry on their faces and when they arrive the trees are ablaze with a dozen different shades of red and orange, so that Minato half expects to see smoke rising above the canopy.
"It's like fire," Kakashi whispers, and the awe and autumn sunlight break slowly into the darkness around him (something human hands can never do), making Minato laugh with joy into the liberating air.
They train beneath ancient trees and unspoiled skies, where the spiteful comments are nothing more than whispers upon the wind (but you can still hear it, if you listen hard enough).
Beneath the slowly dwindling awning of the forest he teaches Kakashi to bring a cyclone of chakra within his hand (he'll always be lightning, though), and thinks that winter is late this year.
It comes without them noticing, within the dead of night so one morning they awake to find the earth cold and unforgiving beneath them. The forest is almost barren now, and it looks naked to them as if the fire has been extinguished and left only the ashes behind. But Kakashi is flushed and bright as fall against the winter cold, and Minato is glad that he has not frozen with the land.
The leave with the first snowfall, because the forest can do without them but the village cannot (oh, they'll see the irony), and Kakashi is drowning comfortably within a too-large shirt because he did not anticipate the winter cold (but he will learn as the seasons come, leave, then come again…).
They return south, their thoughts on a lonely forest behind them, to the village where it is rarely winter. They find the whispers and looks are the same as when they left, and Minato is afraid to see that Kakashi has brought the cold's indifference with him. His eyes are gray and dull as a snowing sky, so Minato makes it a point to drag him out for ramen or show up at his apartment with ice cream in the dead of night.
When Kakashi smiles, rare as it is (and the mask is never enough to stop Minato from seeing), he sees hope that winter will one day turn to spring.