I don’t care how the calendar marks it. As far as I’m concerned, winter starts when it gets Really Freakin’ Cold. Which it did this past weekend. Call it an arctic blast or a blue norther, it’s really cold.
(Also, it tends to blow ragweed pollen down off the Great Plains, adding allergic injury to insult.)
Extreme cold, like extreme heat, is tailor-made for adding both setting details and increasing the level of difficulty for any situation your characters find themselves in. Both physical and mental. It’s hard to aim when you’re shivering so hard your arms are shaking, and it’s hard to think your way through a clock-is-ticking plan when every thought has to crunch its way through ice-crusted snow in your brain.
Not to mention manual dexterity of the bomb-disarming kind very much depends on your nerves, tendons, and muscles all working fluidly – and that only happens when they’re warm. Exposure to cold robs you of this long before you risk frostbite. It adds tension if your character has to decide when to literally take the gloves off, and if they guess wrong….
Don’t leave out fumbles due to stiff feet, toes, or knees, either. Exercise may help keep your core temperature stable, but if your skin is continually stripped of heat, the joints just under it will not be happy.
And that doesn’t even begin to touch the pure glum and grump that may be affecting your character because everything hurts, or just because they hate being cold. Which led to this….
Jason (burrowing under blankets): I’m not getting up this morning. You can’t make me. There’s snow out there.
Writer: …I put you in Korea in the spring. There’s no snow on the ground.
Jason: On top of the mountains. I can see it. Anyway spring here is cold as a Gulf Coast winter, and why did I ever think this was a good idea. Why. I mean, even before the dragon.
Writer: Critical saving throw against depression, remember?
Jason: …Why do you have to think in terms of gamebooks.
Writer: Because good sourcebooks are pure awesome! And I can picture you guys and your world as an Eberron-style sourcebook, artwork and all. Given how bad I usually am with all the visual stuff, that’s got to mean the idea’s working, right?
Jason: Still no excuse for snow.
Writer: I have it on good authority that people get used to the cold. You ought to acclimate in two to three-
Writer: At least your knees can take it now?
Jason: Snow. You know what loves snow? Tigers.
Writer: …Well, yes. The tigers were kind of a given.
Jason: I’d blame Korean historical dramas, except I know you devoured Man-Eaters of Kumaon and never got so much as a nightmare.
Writer: At least you’re not on Lake Baikal?
Writer: Sheesh. You get one little idea for demons rising from the vasty deep of a rift lake and no one trusts you anymore….
Jason: Still not getting up.
Writer: They’ll drag you out. Archery practice. Among other things.
Jason (burrows deeper): They can try.