The last frost date is an average of dates so you can still have a frost after the specified date. The chart at the above link has detailed data for the different states with different temperature thresholds and probabilities. But Mother Nature can be fickle, so if you are putting out delicate plants around the last frost date, watch the weather forecast carefully. If you see that there is going to be a frost cover your plants with upside down milk gallon containers, clear plastic storage boxes or row covers. Just be sure to take off the covers if the next day is really warm. Today is the first day of spring and lots of us are anxious to start gardening. The crocus has bloomed and some of the daffodil buds are starting to open. The tomatoes that I planted on February 2nd, are doing beautifully inside the house and are about 6 inches tall. Last week we had an unseasonably warm day in the 70’s so I set them out to soak up the sun. Just be careful-you really have to watch the weather forecast! See this thread about frost dates for different ideas about when to put out plants. Happy Spring!