The single most useful rule for winter tire timing: switch when daily highs consistently stay below 45°F. Not the first snow, not the calendar date, not Halloween — the 45°F line.
Why 45°F
All-season tire compounds start to lose pliability below about 45°F. Winter tire compounds are designed to stay flexible at that temperature and below. So 45°F is the crossover point — above it, all-seasons grip better; below, winters grip better.
Most parts of the U.S. cross that line in late October to mid-November and stay below it until March or April. Track daily highs for a week — if every one is below 45°F, it's time.
Why not earlier
Winter tires above 45°F wear extremely fast. The soft compound that grips on cold roads basically smears across warm asphalt. Running winters through summer can cut their life from four winters to one, and they handle worse than all-seasons in warm-weather rain.
Why not later
Most winter-related crashes happen on the first cold morning of the season, when temperatures dropped overnight and drivers haven't switched yet. Don't wait for the first snowfall to start thinking about it — by then it's already late.
Switching back in spring
Same rule in reverse. Switch off winters when daily highs are consistently above 45°F and no overnight lows are dropping below freezing. For most of the northern U.S., that's mid- to late-April.
Dedicated wheels save money over time
Mounting and balancing tires twice a year costs $80-120 each time. A set of inexpensive steel or basic alloy wheels — $300-500 for the set — pays for itself in two to three years of seasonal swaps, plus you'll mount the tires fewer times and they'll last longer.
Where to store the off-season set
Stack them flat (if dismounted) or upright (if on wheels), in a cool, dry, dark place. Avoid extremes of heat and direct sunlight. A garage corner works fine for most. Bags help keep ozone off them. Don't store mounted tires lying on their sides — the bead seats can deform.
Watch the temperature, not the calendar. 45°F is the line.