If a TEOTWAWKI situation arises, and planting a successful garden is key to your survival, do you know when it is safe to plant them? The absolute last thin you want to do is plant your precious seeds, only to discover your budding plants were killed by frost, simply because you were unsure of the frost dates.
If you have packed sets of seeds away for a long term emergency, you should pack with it a note of what the frost dates are for your specific area (and whatever area you might move to as well). While some plants are strong enough to survive a late frost, others will be killed by even a slight frost. In a true emergency situation, you won’t have access to the itnernet or the library to look up the date.
If you are in the US, here is the date of last freeze map, to show you the date that the threat of last frost has passed. Here is a much more detailed chart, you select your state and it shows by city. If you live in other countries, just Google “last frost <insert country>” to find the information.
If you consider yourself a beginner gardener, it is always a very good idea to have a vegetable gardening book. It will give you a lot more detail than what you will find on the back of a package of seeds, and it will also give you more information about problems that you might have, such as diseases, pests and just general care tips.