Q: Is this Air Hoar or White Frost??

We had two days of Hoar Frost (or Hoarfrost) last week. This is an example of a specific type of hoarfrost known as "Air Hoar". Wikipedia says it happens when the air is moist and cold and the wind is weak. The trees in front of our house were white and fluffy with frost and the sky was such a clear blue - I had to take a photo.

The next day we had something called White Frost. It only formed on the south side of the trees. Who knew there were so many varieties of frost?

I bet they don't have anything this beautiful in Arizona in the winter. Yeah, yeah - I know - green golf courses in Arizona are quite beautiful when there is snow on the ground in South Dakota.