The average last frost date is an average, meaning that the frost can occur before or after that date. On the news last night they gave a frost warning for our area. I grabbed a bunch of sheets and covered the tender vegetables in the garden.
However, I do not have enough old sheets. So I improvised with some homemade Cloches.
I came downstairs at 6:00 AM, after sunrise, and the thermometer was below freezing.