Answer: Probably about half the time, since it is computed as an average. The frost date is a rough guide for your general area, and as such it is only a reference. Some years provide a late spring with lots of cold snaps and others seem to jump straight into summer. In addition, you might find that the last frost at your house is usually a week earlier or later than the average. This would be a reflection of your local microclimate and is a better indicator than the regional average could ever be!
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