It's cold these days, and this morning I observed the first signs of a light frost. A light frost is when the temperature drops below 32 degrees. Many plants can weather this with out problem. A hard frost, on the other hand, is when the temperature drops below 25 degrees for four or more consecutive hours. Few plants tolerate that well.
You can see the frost on the soil and on the strawberry leaves. These are photos of planted pots. You'll usually observe more frost on potted plants than those in ground due to the tempering aspect of the earth's relative warmth.