Yesterday morning, when we woke up a little before dawn, there was no frost on anything. However, when the late night sky went to clear blue as the sun rose, heavy frost appeared everywhere.
We still had frost/ice on our backyard at 3 pm yesterday. We don’t get a lot of winter sun due to the position of the house and trees for summer.
This morning it is colder and frost was on my Ridgeline and in our backyard before dawn.
>> “However, when the late night sky went to clear blue as the sun rose, heavy frost appeared everywhere.” <<
Common. It happens because the temperature is still dropping until a little after sunrise. We rise at 4:00 normally, and take a 2 mile walk, and have noticed the formation of frost as we are walking fairly often.