Some prepper you are, nukes.
Some years ago we took a rental car on our austin-nashville-MN-austin Christmas trip. Driving through Chicago the washer stops working. Too much sand and shit on the road to see without it. Aha! Lot of people down here just put plain water in them and even if you do use washer fluid stuff that's good to real cold temp isn't even available here. Couldn't buy something good to say -20 if you wanted to.
So we exit and find a place to park. Dig through the luggage and drape all our blankets over the front of the car so they hang down to the ground and trap the heat under there. Run the engine til the washer thaws out. Pump all that shit through and replace it with real washer fluid purchased in a northern state.
Moral of the story:. Always be prepared to fix the car on the side of the road and/or spend the night in it.