Chose a protected spot in a safe area. It should be in close proximity of water but rule out the possibility of flooding. Chose a an area with many plants and, depending on the nature of the apocalyptic event, proximity to abandoned houses or villages can be of advantage because there may be a chance that food and other supplies have been left behind.

You need to be protected from rain, wind and extreme temperatures. Keep all of these aspects in mind when chosing your spot.