But let's not quibble about definitions....as of ~7 a.m., these daylilies were fully and perfectly opened, despite the cool morning air (and despite the fact that I'm not really sure how cool a cool morning should be in my garden in order to record cool morning openers [CMOs]):

EARLY ALIBI (Murphy 2005)
GREYWOODS COUNTRY SQUIRE (Wilkinson 2008)
GREYWOODS ROSEBERRY SORBET (Wilkinson 2000)
GREYWOODS SPIRIT HAWK (Wilkinson 2007) - I mentioned this one in a comment yesterday: how wonderfully it performs. Well, let me add to the praise the fact that it apparently shrugs off cooler weather as well. This is officially the best all-around daylily I've ever grown.
JEALOUS DREAM (Murphy 2007)
MISTER OSCIE (Hensley 2010) - not only opened perfectly, but the first bloom to be thrips-free!
ODDS AND ENDS (Hanson 1999)
PAMELA duCROZAT TREVATHAN (Forrester 2010) - Oh my, how gorgeous! Dark, dark daylily, no dew spots, no thrips!
PERFORMANCE ANXIETY (Hanson 1999) - Supposed to be a ML but has been blooming on one short scape for a while

There were some others as well, but I'm not going to scramble around under plants to find labels....I seem to attract every dog tick and deer tick around!

Some that were almost CMOs, i.e, one slightly wayward petal or something like that:

ARNETTE ZAPEL (Rice 2007)
BUTTERFLIES ARE FREE (Morss 2008) - So far at least, is a perfectly hardy evergreen in my garden
DISCARDED BEAUTY (J. Trimmer 2009)
JEEPER'S KEEPERS (Apps 2006)
WINDHAM TROPICAL WATERS (Matzek 2007)
SEND N CARAMEL KISSES (Strope-Ward 2011) - Too pretty for words, as always
TRIBAL COUNCIL (J. Pryor 2005) - I love this double!
WAITING ON A CALL (Yost 2003)
WAKE UP AMERICA (Schwarz 2003)

EMOs are something I haven't paid much attention to in the past, but it will definitely have some bearing on my purchases from now on. I wonder how many hybridizers classify their daylilies as EMOs?

I don't keep records of temperatures, but our nights are usually cool here. ONE FINE DAY is almost always open on mornings that the rest of the daylilies (excepting possibly some spider or UF types) are shivering. (On the coolest mornings it more or less opens flat, otherwise it slightly recurves.) I suspect that it might be an EMO also, but the truth is that you won't find me out in the garden at 6 or 7 am! (I have to wonder anyway if some EMOs might not be nocturnals that open later at night, as opposed to in the afternoon or early evening.)

ONE FINE DAY is almost done with its initial period of bloom here and in this garden it won't repeat again until October, otherwise I might rouse myself to go check on it early. (Maybe someone else has it and can report on EMO or not?)

There are some days, though, when it is cold enough that even ONE FINE DAY can't bring itself to fully open, which is why I wonder what the benchmarks for CMOs are.

GREAT topic, by the way... I'd love to learn more about CMO and EMO daylilies: what the standards are (if any) for registering as such, and what are some good cultivars with the traits. I've had it with daylilies that can't handle our cool nights, and want to incorporate the CMO, EMO traits into my seedlings.