There was light, scattered cirrus that prevented a lot of photometry during
the first half of the night. Spectropolarimetry was largely unaffected.
Around midnight, a thicker band of clouds rolled through and slowed
progress for about an hour. After that, the sky was mostly clear until the
start of morning twilight, when the thickest clouds of the night forced an
end to observing about 20 minutes early. Winds picked up to 30-40mph after
midnight, but were not a factor. The seeing started out at 1.7 arcsec and
improved to 1 arsec or better during the middle portion of the night.
By the end of the night, the seeing was around 1.5 arcsec.