A poetry professor told my class once that most students sign up for poetry classes in either the spring or the fall trimesters. Maybe it's something about the ever-changing weather that sparks thoughts of transience in young writers; it's not clear.
But it's a different story—no pun intended—with prose. In works set, in whole or in part, outside Earth as we know it, extremes of climate can be a quick and effective way to convey that a setting is fantastic. If it's not a place that's very important to the plot, the setting itself can be static (the Star Wars characters didn't stay long enough on Hoth for global warming to set in). However, creating an extreme setting can serve to set up changes brought about by the plot of a fictional work. For instance, in The Lion, the Witch, and the Wardrobe it is “always winter but never Christmas” in Narnia for a hundred years, until the arrival of Father Christmas heralds that something new is on the way.
The permanence of winter and summer, and the significance of changes thereof, are taken to even greater lengths in the appropriately-titled Summerland, by Michael Chabon. The novel begins in the corner of an island in Washington State, known as “Summerland” for its freakish weather. “It never rained. Not even for a minute and a half,” we are informed on page 14. By page 35, the first chapter ends by telling us “where every summer for as long as white men could remember there had been an endless supply of blue sky and sunshine, it had started to rain.”
It turns out that the Summerland in our world is not the only setting of the story. Instead, it serves as a “gall,” a spot “where two worlds flow into each other,” and a gateway to the Summerlands, plural, a world as grand and important as the entire universe as we know it. There are two other worlds, including the Winterlands, containing “a limitless expanse of ice, a hundred or a thousand or ten-thousand miles of jagged ice teeth.”
Besides the weather, Summerland and Narnia share another feature in common: the time spent inside one world will not necessarily relate to the time elapsed on Earth between your departure and reappearance. In Summerland, I feel like this is done so that the author has more freedom in choosing when his characters return to Earth (in having one character return before he leaves, Chabon goes beyond even Lewis' most impressive time-dilation feats). Indeed, the various rates of time can be used for more descriptive and less “scientific” narration; another character's “beard grew at Winterlands speed, half an inch per day.” When I reread this line I played the “free association” game, imagining the Russian tundra and bringing along lots of associated, exaggerated images for the next few lines. Chabon uses over-the-top descriptions of both space and time to let the reader bring well-known mythology to the table.
Both Summerlands and Winterlands are threatened by the Coyote, Chabon's hodgepodge of mythological tricksters. Because of their in-universe construct as places named after seasons but with their own independent existence, rather than just characterized by their climate, they can be damaged by actions of the Coyote and his minions in more creative ways than just changing the weather. When Coyote and his troops turn ferishers, a species native to the Summerlands, into skrikers and graylings (other types of creatures), this is a threat to the Summerlands on par with any other fantasy novel, not constrained by the seasonal themes.
Similarly, since Winterland is within the context of the story a place, “the end, and the start, of the Winterlands” is also a place; an “in-between land” called “the Greenmelt.” Chabon withholds this description until Chapter 23 (of 25). Although the characters don't wind up spending much time there, it serves as a symbolic “end of winter” in a geographical rather than a temporal sense, and describing it so late in the story makes it seem like an appropriate sign of the “end of the journey.”
There are a wide variety of magical changes enacted to the four worlds at the end of the book, but unlike in Narnia, the Winterlands don't stop being fundamentally wintry. We hear very little about how, if at all, it changes; one character who in particular does not immediately benefit from the wave of magic is specified as “lying on a barren patch of ice at the edge of the Winterlands.” The wintriness and summeriness of the respective “lands” outlast the book, which makes sense; while Narnia's winter is implied to be an unnatural and unwelcome sign of the White Witch's rule, the Winterlands and Summerlands aren't inherently good or bad; they simply are.
Of course, these extreme settings throw the vagaries of our own world into even sharper relief. In Summerland, our universe is called “The Middling,” neither fully hot nor cold. We are reassured by a werefox in Chapter 2 that it is still his “personal favorite of the lot,” and Chabon later describes it as “broken and beautiful.” I think this kind of description is trying a little too hard; when the magic of the world is primarily defined by its overlap with others, being reassured by adults that flaws are just part of the beauty comes off as a little patronizing. Overall, though, Summerland is still an adventure for all seasons.