I believe this is my third time photographing a lunar halo - my first time was most impressive visually but faded when I went back inside to get my camera. My second time was a bit better last November in Brownsburg.
This time my lunar halo wasn't broken up by a contrail, and was clear enough to see the rainbow (or 'moonbow') effect of the light splitting into different wavelengths. These lunar halos can happen throughout the year, because the upper atmosphere can be cold enough for ice crystals even when the temperature below is much warmer - but I've only ever seen it in the colder months.
|Single frame with Canon T5i, ISO 800, 18mm, f/4, 2.5 sec|
|Lunar halo with iPhone and NightCap app|
|Close-up of the lunar halo moonbow, single frame with Canon T5i, ISO 1600, 55mm, f/5.6, 3.2 sec, saturation and contrast tweaked in iPhoto|