I'm not really qualified to go into the whys; there are a number of possibles. Try using a winter oil (5W-xx or 10W-xx) and run a tank of super unleaded through it. run gas line antifreeze in tank if it's really cold, also if you have fuel injection it may be a faulty temp. sensor, if it's a carburated vehicle it could be the atomatic choke not working as it should, but yeah 5w30 oil is good for the cold season :)
There are a few reasons why a car might stall when cold. The car might just be stiff from the cold weather.
Metal expands when warmed and contracts when chilled.
It means the engine stopped running.
Faulty ECT (engine coolant temperature) sensor. Replace it.
Yes you do, your muscles are not properly warmed up compared to hot weather and your breathing becomes shorter.
bad fuel filter
1st try checking the EGR valve. If the EGR valve is sticking or leaking it can force too much air into the air/fuel mixture causing the motor to stall out.
if you are talking of outside, you can build something like a lean-to or small open barn or the horse to shelter in bad weather or from cold. but if you can, in bad weather or cold keep your horse in its stall in the barn.
A stationary front
it'll run very badly in cold weather, and may stall due to excess fuel in warm weather
It could have fallen out of time, could need new spark plugs and wires.
A cold blooded reptile basking on a warm rock is being warmed by the sun's heat.