For the past two nights, I've covered my tomatoes and peppers. I carried six terracotta pots out of the henhouse and turned them upside down over the plants before I came in for the day. I also did the same with six lavender plants Mom started on our inside porch last winter.
I removed them each morning before the sun got too "hot".
Friday night we had a low of 37° and I didn't see any frost.
Last night, Dan (who lives about four miles north of me) recorded a low of 36°. Another electronic weather station in Farmersville recorded 37°. Mom said that's the lowest she saw on the thermometer we have mounted outside the kitchen window. Obviously it got colder.
When I took garbage out to the compost hole in the garden at 7:30 am, I was amazed to find the rainwater in the top of our burn barrel (a 55 gallon metal oil drum) was frozen.
I tried to lift the edge of the ice so it would better show in this photograph. But it was thin and brittle and it cracked whenever I tried to break surface tension with it. Still, I think you can see that this is ice.
The burn barrel is open to the full sky and removed from the house. It sits at the edge of the garden and on the north side of the garage. It could not have frozen unless the temperature in that spot made it down to 32°.
As I looked across the lawn (mowed yesterday), I saw patches of white frost in the back yard, though nowhere else.
The "date of last frost" for the Dayton area is generally considered to be May 15. It is most common in late April but seldom beyond the first few days of May. I understand the record late frost for our area was May 21. So, unusual as frost may be, it can happen.
Still, the recorded lows do not show this happening. And yet, here at Pinehaven, it did.