This morning was our first heavy frost of the season. We've had a couple of mornings with very light patchy frost, the frost was unmistakable this morning. The low this morning was 29.7 degrees. I don't know if this counts as a killing frost though since we really hovered at or above 30 for most of the morning. The flowers on my deck were covered in frost this morning.
A new astronomical surprise this evening that has even shocked the professional astronomers. Comet Holmes has exploded in magnitude. This article explains that the comet was at a very dim magnitude 17, but has exploded into a magnitude 2 sky object. You can see a star chart giving the location of the comet here. Look for Cassiopea and then down and to the right just a bit. It is in the constellation Perseus. I went out just now and found it in 2 seconds. It is a blurry disk shaped object in the sky. They say that if a tail develops, it will be very short and stubby. We are looking directly at the comet from Earth and the sun is behind us. They say that from the comets point of view, the Earth is only 15 degrees apart.