The average dates are established at the 50% level or half the times the frost may occur before or after that date. The safe date is when there is less than a 10% chance the frost will be after (for last frost) or that it will occur before (the first frost). You certainly will have your own little micro-climates around your landscape to modify your planting times. You can always use season extenders to modify these areas. These techniques are not limited to greenhouses or row covers.
|Location||Average Last Frost (Date)||Safe Last Frost (Date)||Average First Frost (Date)||Safe First Frost (Date)||Average Growing Season (Days)||Safe Growing Season (Days)|