The trunk kit: what rides in the car from November to April

The winter car kit is three layers that live in the trunk from the first freeze to the last: the layer that gets you seeing out, the layer that gets you unstuck, and the layer that keeps you alive if neither works. None of it is expensive and most of it fits in one bag. Pack it in October, because the first time you need it is the night you discover you do not have it.

Seeing out first. A telescoping snow broom with a scraper on the other end, the Snow Joe SJBLZD here, sweeps the roof and hood without scratching paint and reaches across an SUV. Pull the foam head toward you rather than pushing from the side, because the head unscrews under side load, which is the complaint in its reviews. Clear the roof every time: a slab of snow that slides onto a windshield at speed, yours or the car behind you, is how winter rear-end crashes happen, and several states, New Jersey and Connecticut among them, fine drivers for it. Swap the washer fluid for one rated to minus 20 or colder before the first freeze; summer fluid freezes in the lines at 32 and the pump cannot clear it. A spare jug rides in the trunk, because road salt spray empties a reservoir in a week. Fresh wiper blades in the fall, and never pour hot water on a frozen windshield.

Getting unstuck. The AutoSock 685 is a pair of textile covers that go over the drive tires in about a minute without jacking the car, accepted where chain laws apply, and good for the snow-covered stretch only: they shred within a few miles on bare pavement and carry a 30 mph limit, so they come off the moment the road clears. Check the size against your tires first; the 685 is one of ten sizes. Under the socks goes a small folding shovel to dig the tires out and clear the tailpipe, and a bag of sand or coarse kitty litter for weight over the drive wheels and grip under a spinning one. Floor mats work in a pinch. Check tire pressure monthly all winter: it drops about one psi for every ten degrees, and the tire that was fine in September is under-inflated in January.

Power. The cold is what finds a tired battery: a three-year-old battery that started fine in August can quit at zero. Have it load-tested at a parts store in the fall; the test is free and takes five minutes. Then carry a lithium jump starter in the glovebox, a 1,000-amp class unit rated for your engine size, and charge it every two months, because a jump starter that was full in November is half-empty in March. Add a charging cable for your phone and a power bank, since the car's own battery is the thing that just failed. Our jump starter pick is in research and lands here when verified.

Staying put. If the car is stuck in a storm, the advice from every state patrol is the same: stay in it. It is shelter, it is visible, and walking for help in a whiteout is how people die a few hundred yards from a road. Run the engine about ten minutes an hour for heat, with the tailpipe cleared of snow every time and a window cracked, because carbon monoxide from a buried exhaust kills people inside a running car. The kit for that night: a wool or emergency blanket, a pair of hand warmers, water, a few bars, a headlamp, a reflective triangle, and the gloves and hat you would not otherwise be wearing. A pre-packed emergency bag with jumper cables, a flashlight and first aid is a fine base to add those to; our pick for one is in research.

Two habits cost nothing. Keep the tank above half from November on: it is weight over the rear wheels, it is hours of heat if you are stuck, and it keeps condensation out of the fuel. And winter tires. They are not on this site, because the right size depends on your car, but a set of winter tires on a front-wheel-drive sedan stops and turns better on snow than all-season tires on an all-wheel-drive SUV. If you buy one thing for the car this winter that is not on this list, it is them.

The whole kit, in the order it goes in the bag: snow broom and scraper, winter washer fluid, AutoSock or chains sized to your tires, folding shovel, a bag of sand, jump starter and cable, blanket, hand warmers, water and bars, headlamp, triangle, gloves and hat. Pack it in October, check the jump starter charge on the first of every month, and take it all out in April so the washer fluid does not ride around all summer.