Most winterizing advice assumes you have a garage. Plenty of people around here do not, and the cart still has to get through to April.
It can be done. It just takes a bit more thought.
Get it off the dirt
This one matters more than the cover. A cart parked on bare ground sits in months of wicking moisture, and that is how frames start to go, especially older steel framed carts where the battery rack already takes acid drips.
Gravel is better than dirt. A concrete pad or even a few sheets of plywood on blocks is better again. Anything that breaks contact with wet ground.
The pack does not have to stay with the cart
This is the biggest advantage you have. Batteries are the part that genuinely suffers outdoors, and they are removable.
A fully charged lead acid battery will not freeze, but if it drifts down over the winter it can, and a frozen battery is a dead battery. If you have anywhere above freezing to put the pack, a basement corner or a heated shop, take them out and put them on a maintainer. That removes the entire risk.
If you cannot, charge the pack fully and reset the charger about once a month.
Cover it, but let it breathe
A tarp strapped tight to the ground is worse than no cover. It traps moisture, and the cart sits in a damp tent all winter growing mould on the seats and rust everywhere else.
You want something that sheds snow off the top while air still moves underneath. A proper cart cover is best. A tarp over the top with the bottom left open is a reasonable second.
Angle it so snow slides off rather than pooling. A flat tarp collects a couple of hundred pounds of wet snow and the poles and the top take the load.
Mice, and outdoors this is worse
An outdoor cart is a warm dry hotel to every rodent in the neighbourhood. Steel wool in any opening, dryer sheets under the seat, and set traps nearby. Check them.
Chewed wiring is the most common expensive spring surprise I see on outdoor carts, and it is entirely preventable.
Tires and brakes
Air the tires to spec so they do not flat spot, and leave the parking brake off. Brake shoes left engaged all winter in the damp can seize to the drum.
Chock a wheel instead.
Clean it first
Grass and mud packed under the cart holds water against metal for five months. Give it a wash, get the underside, and let it dry before you cover it.
If that is a lot
It is a lot. That is what the seasonal package is for, and I do outdoor stored carts all the time. Call and tell me where it sits and what you have available.
406.270.9346.